Maximum capacity going down rapidly

Battery health is notoriously difficult to measure outside a proper test workshop, so what you see is probably quite normal. I expect to see at least 5% tolerance on the estimate, and it is likely to also be sensitive to temperature so you can see different answers on different days.

Apple usually considers a battery should be replaced when it drops below 80% health, so yours is getting low but still within tolerance.

iPhone Battery and Performance - Apple Support

Plesae, remember that that value is related to when the battery (not the iPhone) was new.

That said, read this support article very carefully:--> iPhone Battery and Performance

These are the suggestions you should follow to slow down your battery's degrade:--> Batteries - Maximizing Performance and/or:--> When to charge your iPhone or iPad - Apple Community

When the maximum capacity goes down below 83%, I suggest that you create a full backup of your device on a regular basis (at least once a week), because the battery could have unpredictable behavior and stop woking suddedly.

Form more information (even for getting an estimate) about your battery replacement:--> Choose Your Country or Region - Apple Support

Regards

Giulio

Alex ~ Did you buy the iPhone SE 2020 new or used? ...If used, you can check if the battery has been replaced. Go to Settings > General > About

...Does it say anything about the battery?

iPhone parts and service history - Apple Support

...Found by searching Apple's Knowledge Base.

õ¿õ¬