iPhone 7 battery suddenly dropping to <10%

My iPhone 7 (iOS 15.7) has said to service the battery for awhile but has been functioning fine until last night.

My battery suddenly dropped from ~70% to 1% around 6:30pm while it was locked. I last had Life360 (location tracking app) up so I figured it was due to that (battery usage lists Life360 at 100% before it drained). I charged my phone until ~85% & everything seemed fine.

Around 11:50pm, my battery dropped from ~70% to 12%. Looking at the battery history graph below, it looks like it first dropped from 70% to 45% & then down to 12%.

The app usage doesn't list any %:

Now, I'm thinking it's an issue. I plugged my phone in to charge again & it basically shoots back up to 80%.

I didn't use my phone from 12:30-3am, where the graph has 0 data below.

My battery was reading ~75% so I left it unplugged overnight.

I woke up to my battery reading 1% at 10am. Checking the graph, it dropped from 75% to 25% & then was ~10% or less for around 4 hrs (I doubt my phone could actually last that long in the red before shutting off).

Checking the app usage, it shows several random apps (Whole Foods, Google Sheets, etc) w/o background app refresh. My apps do not auto update; I had manually updated several earlier the previous day but none listed were updated.

----> does this appear to be due to a severely degraded battery? Or is this a compound issue?