Well, there is a way, but it’s a bit ugly, so sorry for that, but I can’t come up with a cleaner way at the moment.
I’ve created a small example how to change the keys in the state_dict:
# Create Sequential model
modelA = nn.Sequential(
    nn.Conv2d(3, 6, 3, 1, 1),
    nn.ReLU(),
    nn.Conv2d(6, 12, 3, 1, 1),
    nn.LogSoftmax(dim=1))

# Create Module
class MyModel(nn.Module):
    def __init__(self):
        super(MyModel, self).__init__()
        self.conv1 = nn.Conv2d(3, 6 ,3, 1, 1)
        self.conv2 = nn.Conv2d(6, 12 ,3, 1, 1)
    
    def forward(self, x):
        x = F.relu(self.conv1(x))
        x = self.conv2(x)
        return F.log_softmax(x, dim=1)


modelB = MyModel()

from collections import OrderedDict

# Get Sequential state dict
state_dict = modelA.state_dict()
for keyA, keyB in zip(modelA.state_dict(), modelB.state_dict()):
    print('Changing {} to {}'.format(keyA, keyB))
    state_dict = OrderedDict((keyB if k == keyA else k, v) for k, v in state_dict.items())

# state_dict should keep the old values with new keys
modelB.load_state_dict(state_dict)
print(modelB.state_dict())

Could you try that?