A friendly reminder that isps do NOT care about you or your digital rights. Always best to buy directly from the OEM rather than from the telecommunications (unless you can't afford it). Do proper research before buying a phone!
The best thing is actually to buy a used phone that was really good a couple years ago. I bought a used Oneplus 9 for $200 last year and it's still perfectly usable and way more powerful than I've ever needed a phone to be. Also older phones are more likely to be supported by third party android distributions.