I didn't realise until about 10 years ago that you can freeze milk - heard two women behind me on the bus discussing it!
I keep a couple of the two-pint plastic bottles in the freezer - word of advice it takes many hours to defrost so take it out before bed and leave on the draining board if needed for the morning.
I keep milk in the freezer, but I do find that it goes off very quickly after defrosting.
Not living near a shop, and reliant on a three-weekly (if i was lucky) delivery for all our food, including milk, I started keeping quite a stock of milk in our freezer during lockdown. I started this after they weren't able to bring me a single bottle of milk of any kind with one delivery.
I wrote a number or letter on every bottle (plastic), indicating which order they should be used in.
This worked really well for ages, though I had to check for splits in the bottles before thawing, and defrost in a large container just in case.
However, after a largely problem-free year of doing this, and despite the milk not being 'old', we started getting an increasing number that just didn't taste right when thawed. I have no idea why. The freezer temperature was still perfectly OK.
Anyway, we stopped doing it because of that and now keep a reserve of long-life cartons instead, though still making sure that they are not kept too long and using oldest first.