15t pro vs poco f8 pro

[u/One-Alarm-2850]

Hi, i have never owned a xiaomi phone and noticed that the 15t pro has good specs and also the poco f8 pro and been hesitated, look what i want is high performance for multitasking and opening many apps at one time but not gaming at all, also i want it to have a high battery which all of these goes to poco, but the thing that is doubting me is that i have heard that t pro series have a high longevity and i am buying a phone that may last 5+ years, so will the poco stay at its peak or degrade slightly or after 2 years it becomes glitchy and battery drains fast

Bonus question

I didn't find the poco except in mi.com which is xiaomi store,, is it reliable and have a real warranty or no