This may just be me being retired and away from tech too long and you guys with Samsung phones may know this, but:
For the past few days, I have been having ridiculous overnight drains on my phone. I generally attribute it to crappy apps like SiriusXM not working right, so just reboot the phone. However when it happened this morning, I decided to see which app was doing it. None of the usual culprits.
Instead, I saw "customization service". Never heard of it. Some googling showed it to be the Samsung equivalent of Google's intrusive "personalization services". Super intrusive and ties in to a ton of stuff on the phone. It is apparently automatically turned on when you accept Samsung's terms of service. Now I'm generally pretty good about going through settings to turn off intrusive stuff like that. Only this isn't in normal settings. To turn it off, you have to go to "Gallery" (as in photo gallery) and go to settings there. Totally unintuitive.
I noticed that in the past several weeks I have gotten several updated Samsung terms of service notices to agree to. I'm almost wondering if I did turn this off when I first got the phone, but it was reactivated with the new terms of service.
Anyway, just an FYI about a creepy app if you weren't aware. Gallery/settings/customization services