Ridiculous battery drain/discharge rate with no clear culprit?

Recently, my iPhone SE 2020 started discharging at an alarming rate, for apparently no reason (according to battery information).

It literally can go from 100% to 0 overnight in low power mode. It'll shut down in the middle of the night and my alarm won't wake me up.

As you can see in this screenshot, battery settings only reports that translate is used overnight, but actually this is the first night where that was the case. On other nights it showed nothing being used at all.

My battery health is 88%. I have almost religiously not to charged my battery past 90% or discharged below 10%. Since I bought almost a year ago, I can count on 1 hand how many times I have charged it overnight... but now it looks like I will have no choice but to leave it charging overnight, otherwise I will be waking up to a dead phone every morning, and one night I remember it reporting another app running 5 minutes in the background every hour.

Not even a few weeks ago I could leave it at a 40% charge before going to sleep and I could wake up to something like 30-35%. This change is very sudden and very drastic. I have doubts that it would be directly related to the condition of the battery, but perhaps?

It's hard to say if this came immediately after an update...

Does anybody have any suggestions/ideas? What's going on here?

Thanks for checking this post out!