Arturas_Druteika:

To my understanding normal convolutional operation has as many unique filters as there are input channels.


That’s not the case, as a “standard” convolution will use filters, which use all input channels by default. The out_channels define the number of filters. CS231n - Convolutional Layers 2 describes this in more detail.
Depthwise convolutions with groups=in_channels would use filters, where each group is applied to on input channel only. Since the parameter count is reduced you are often applying a 1x1 “pointwise” convolution, which is applied in the “standard” way afterwards.