Apple Watch Series 3 stuck on a bootloop, not holding charge

So I got a hand me down Apple Watch Series 3, it’s stuck in a boot loop, as in apple logo comes on then fades away in red, sometimes it doesn’t do that, I tried to force reset it holding the crown and the button, didn’t do anything, once a red exclamation mark did show up, then it went away, sometimes the bootloop varies, it lasts like 1s or 5s or even like 15s, I left it in the charger for like 30 mins, but it heated up a lot, this is the stainless steel version of the watch