One of mine is the base 11 purchased within a month or so of release (was excruciatingly close to getting a 13 pro max but that’s a different discussion
). My battery health is mid 80s but the charge almost always lasts until the evening sleep charging (using Qi charger for much of its life). But if it’s under heavy use (connected to the AirPods playing music for hours, extra long conference calls etc), it can get too low by mid evening. If this is your use case and daily battery experience, I’d say you’re getting what you’ll get from the device.
Did you just apply an OS update? For me I noticed it drained quicker until an added reboot a day or two later.
Do you have optimized charging disabled? (this won’t help the battery now but will moving forward)
Do you have the screen brightness on manual and turned up high?
Are you on carrier internet a lot especially where the signal gets off and on poor coverage?
It may be worth checking that your phone’s settings aren’t draining the charge quicker than need be.
If all that is good but it still regularly isn’t giving you enough daily battery juice, as ED7789 said, it may be time to think battery replacement. Even better, imho, trade in your 11 for the better battery of the 13. Apple before Christmas was offering 350 for trade. Add in the cost of battery replacement and your within a couple hundred of a new 13 (it’s charge likely exceeds a new 11 significantly). BOL…