I’m pretty sure you’ve assumed right. A lot of builds of Android 12 will warn you if you’re over a safe limit, but it’s very possible that Motorola (who keep things pretty close to stock Android) probably have something that’s knocking it down back to a ‘safe’ level after some bit of inactivity.
You may have a setting to disable it in the developer menu, usually accessed by tapping the build number in the “About” section of the settings menu a couple dozen times until it says “you are now a developer!” - and then checking there. Anything beyond that is gonna require root/rom or other trickery.