Chromebook battery and software issues.

My chromebook (brought in Febuary ish of 2019) has been having a few issues recently. During school it freezes and crashes whilst I do light work on it, and lately it hasn't been charging. I've been using the same charger for about a year now and it's been good so far. Except my chromebook doesn't seem to hold its battery anymore, and I can charge it for hours. But when I try to turn it back on it either:

1. Doesn't turn on whatsoever
2. Turns on for a short while but crashes or runs out of juice before I can even enter my password.

I've tried doing system reboots and reinstalling ChromeOS versions, I've even powerwashed it. But nothing I do seems to work.

Please help!!!