Your question is a bit all over the place.

If you’re just looking for big amounts of storage, look for refurbished HDDs (4TB, 12TB, something like that).

You could say that.

Ah yes, true. But it is a whole year, so you’d only need to login once a year.

And what would be a situation where you have to enter a phone number? I only know it’s optional for account recovery.

As far as I know they delete the account if you don’t log in for a few months.

I mean, without the additional requirement Proton may be sufficient.