I’m still using my OP7T as well, as a game machine. Unfortunately it gets super hot, to the point of leaving red scorch marks on my hands.:-( It could be the battery deteriorating I suppose, but one day it literally never happened, then the infamous update occurred and now it never not happens - you surely know the one if you’ve had the device since it came out (the one just after which the cofounder left the company in protest). That update somehow (melting some internal shielding? it got so hot immediately after/during that update that I genuinely thought it might explode!!?!) turned my beautiful phone with the literal best balance of specs for price among all Android phones, into something that I cannot use for more than a few minutes at a time. Tbf the game that I play on it likely has gotten worse over time in how much processing it demands.

But if yours still works… then kudos bc that phone was really something, for its’ day and even now.:-)