I’m a complete and utter newbie to this. But, based on the discussion about “not needing a new phone” and the availability of alternatives in Canada, can anyone recommend what might act as a suitable alternative to Android and iPhone OS. Ideally, I can keep my phone and just use a different OS. But I have some problems and could use some foundational knowledge to start my research and make a decision:

1. I’m trying to keep my Samsung S21 Ultra as long as possible. I looked at Graphene and Lineage and both do not support it from what I can tell.
2. Internet, heavy data use is not an issue. I have wi-fi wherever I go.
3. I’d prefer not to buy a new phone. If I need to buy a used phone, I am leaning towards an older Pixel and Graphene OS. Is that a sound decision? If not, are there phones such as Fairphone (not in Canada…) to consider?