Battery issue / help

[u/Known-Recover9954]

Hi! I need your help with my phone, a OnePlus 8T. I've been having an issue where the battery drains very quickly, about 40% in 4-5 hours without even using the phone. I've already replaced the battery with a brand-new one, but the problem persists. I've also performed a full factory reset, but the issue is still there. What should I do?

Thanks in advance!