OnePlus. My 6T still works perfectly. No issues after 4 years of use, even the battery still lasts a good time. Sometime after they dropped support (since it's an old model), I installed DivestOS and it still works great, updates and all. Became my backup phone. I got myself a Nord2T now, and I like it a lot, I have the impression it will last forever too.

I had a Samsung in the past, but I had some issues with it.

Btw, I never buy top of the line phones.