I also profiled the code (Conv2ds & nn.Sequential using Profiler) and got the following outputs for three Convs.
with torch.profiler.profile(activities=[torch.profiler.ProfilerActivity.CPU]) as prof:
    model(x)
print(prof.key_averages().table(sort_by="cpu_time_total", row_limit=30))

------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
                          Name    Self CPU %      Self CPU   CPU total %     CPU total  CPU time avg    # of Calls
------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
                  aten::conv2d         0.06%      17.000us       100.00%      26.736ms      26.736ms             1
             aten::convolution         0.03%       9.000us        99.94%      26.719ms      26.719ms             1
            aten::_convolution         4.74%       1.268ms        99.90%      26.710ms      26.710ms             1
    aten::_convolution_nogroup         4.35%       1.164ms        83.49%      22.323ms     286.192us            78
             aten::thnn_conv2d         1.56%     417.000us        78.83%      21.077ms     270.218us            78
     aten::thnn_conv2d_forward        46.99%      12.564ms        77.27%      20.660ms     264.872us            78
                  aten::narrow         3.66%     978.000us        10.84%       2.899ms      12.336us           235
                  aten::select         7.99%       2.136ms         9.32%       2.493ms      10.654us           234
               aten::unsqueeze         6.30%       1.685ms         7.59%       2.029ms       8.671us           234
                   aten::slice         5.56%       1.487ms         7.19%       1.921ms       8.174us           235
                  aten::addmm_         5.55%       1.485ms         5.55%       1.485ms      19.038us            78
              aten::as_strided         4.25%       1.135ms         4.25%       1.135ms       1.615us           703
                 aten::reshape         1.73%     463.000us         2.31%     617.000us       7.910us            78
                 aten::resize_         1.78%     477.000us         1.78%     477.000us       3.038us           157
                   aten::copy_         1.76%     471.000us         1.76%     471.000us       6.038us            78
                   aten::empty         1.41%     378.000us         1.41%     378.000us       1.609us           235
                    aten::view         1.16%     311.000us         1.16%     311.000us       1.994us           156
                     aten::cat         0.33%      88.000us         0.86%     230.000us     230.000us             1
                    aten::_cat         0.45%     121.000us         0.53%     142.000us     142.000us             1
       aten::_nnpack_available         0.31%      82.000us         0.31%      82.000us       1.051us            78
------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
Self CPU time total: 26.736ms

------------------------------  ------------  ------------  ------------  ------------  ------------  ------------

                          Name    Self CPU %      Self CPU   CPU total %     CPU total  CPU time avg    # of Calls

------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
                  aten::conv2d         0.34%      11.000us       100.00%       3.214ms       3.214ms             1
             aten::convolution         0.34%      11.000us        99.66%       3.203ms       3.203ms             1
            aten::_convolution         0.50%      16.000us        99.32%       3.192ms       3.192ms             1
    aten::_convolution_nogroup         0.96%      31.000us        98.82%       3.176ms       3.176ms             1
             aten::thnn_conv2d         0.34%      11.000us        97.48%       3.133ms       3.133ms             1
     aten::thnn_conv2d_forward        19.88%     639.000us        97.14%       3.122ms       3.122ms             1
                   aten::copy_        55.54%       1.785ms        55.54%       1.785ms       1.785ms             1
                  aten::addmm_        18.20%     585.000us        18.20%     585.000us     585.000us             1
                  aten::select         0.65%      21.000us         1.28%      41.000us      13.667us             3
              aten::as_strided         0.84%      27.000us         0.84%      27.000us       4.500us             6
                   aten::empty         0.59%      19.000us         0.59%      19.000us       6.333us             3
               aten::unsqueeze         0.31%      10.000us         0.53%      17.000us       5.667us             3
                    aten::view         0.44%      14.000us         0.44%      14.000us       2.800us             5
       aten::_nnpack_available         0.37%      12.000us         0.37%      12.000us      12.000us             1
                 aten::resize_         0.34%      11.000us         0.34%      11.000us      11.000us             1
                 aten::reshape         0.28%       9.000us         0.34%      11.000us      11.000us             1
                  aten::detach         0.06%       2.000us         0.06%       2.000us       2.000us             1
------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
Self CPU time total: 3.214ms

------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
                          Name    Self CPU %      Self CPU   CPU total %     CPU total  CPU time avg    # of Calls
------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
                  aten::conv2d         0.01%      15.000us       100.00%     175.729ms      87.865ms             2
             aten::convolution         0.01%      16.000us        99.99%     175.714ms      87.857ms             2
            aten::_convolution         0.77%       1.348ms        99.98%     175.698ms      87.849ms             2
    aten::_convolution_nogroup         0.66%       1.156ms        97.28%     170.944ms       2.164ms            79
             aten::thnn_conv2d         0.28%     488.000us        96.58%     169.724ms       2.148ms            79
     aten::thnn_conv2d_forward        91.71%     161.165ms        96.31%     169.236ms       2.142ms            79
                  aten::narrow         0.60%       1.056ms         1.80%       3.169ms      13.485us           235
                   aten::copy_         1.21%       2.133ms         1.21%       2.133ms      27.000us            79
                   aten::slice         1.03%       1.810ms         1.20%       2.113ms       8.991us           235
                  aten::select         0.79%       1.394ms         0.96%       1.689ms       7.127us           237
               aten::unsqueeze         0.78%       1.373ms         0.95%       1.662ms       7.013us           237
              aten::as_strided         0.50%     887.000us         0.50%     887.000us       1.251us           709
                  aten::addmm_         0.50%     874.000us         0.50%     874.000us      11.063us            79
                 aten::reshape         0.29%     516.000us         0.42%     734.000us       9.291us            79
                 aten::resize_         0.29%     504.000us         0.29%     504.000us       3.190us           158
                    aten::view         0.22%     386.000us         0.22%     386.000us       2.398us           161
                   aten::empty         0.18%     310.000us         0.18%     310.000us       1.303us           238
                     aten::cat         0.06%     106.000us         0.14%     246.000us     246.000us             1
                    aten::_cat         0.07%     123.000us         0.08%     140.000us     140.000us             1
       aten::_nnpack_available         0.04%      64.000us         0.04%      64.000us       0.810us            79
                  aten::detach         0.00%       5.000us         0.00%       5.000us       5.000us             1
------------------------------  ------------  ------------  ------------  ------------  ------------  ------------
Self CPU time total: 175.729ms