My watch 4 series dying quickly after pairing with Iphone 15 Pro

Hi all! I recently upgraded my trusty Iphone 11 to the 15 Pro and after pairing my 15 Pro to my Series 4 watch, the battery life has plummeted. Before the battery drain, my battery had a life of 88%, and now is down to 87% this past week. I can maybe get 4-5 hours out of the watch at a time now. It also happens to run very warm now, something it would only do after charging or updating. I’ve so far done the hard reset, setup as a new watch (deleted all the apps on it for now) and there’s no difference in battery life still. Considering my watch is about 5+ years old, should I just bite the bullet and upgrade to a new one?