And don't get me started on UHT milk. I don't know why it is my husband's preferred choice, but we always take 3 or 4 UHT soya, and 4 UHT cows milk. Since the crisis began we have only been able to buy fresh cows milk in plastic containers.
If the (cows) milk has been homogenised and is in plastic bottles it is normally ok to freeze them - check the label though to make sure it is ok. And best to do some research online about how to freeze and how to defrost etc.
And never use glass bottles in the freezer.

The defrosted milk sometimes has a different flavour and texture to fresh milk, but if UHT is normally preferred I'm not sure the difference will be noticeable. Often better results can be had from skimmed or semi-skimmed milk - the fat content is part of the problem.
I don't know about freezing other kinds of milk, but I'm sure the internet has all the answers somewhere.