Yes, you are right. If you are padding the image so that it has the same height and width, a single value in Resize should work.
Could you add this my_print transformation to check which shapes are used?
def my_print(img):
    print(np.array(img).shape)
    return img

transform = transforms.Compose([
    transforms.Lambda(lambda x: my_print(x)),
    imaugs.PadSquare(p=1),
    transforms.Lambda(lambda x: my_print(x)),
    transforms.Resize([384], interpolation=transforms.InterpolationMode.BICUBIC),
    transforms.Lambda(lambda x: my_print(x)),
    transforms.ToTensor(),
    transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
])