What does iCloud *not* backup for iOS?

So I know what iCloud does backup: https://support.apple.com/en-us/HT207428

But I couldn’t find any source on what it doesn’t backup

I accidentally bricked my phone and loaded my backup onto another phone (it’s been a while), but I did notice a few things (I’ll continue adding things to these lists as I use my phone, in case anybody wonders the same thing):

Things that did not backup/move over to new phone:

1. There was no call history, that didn’t get backed up
2. Apps that were no longer available in the app store did not get backed up
3. Apps that I had developed and deployed to my phone were not backed up (icons still there, though)

Things that did backup/move over (somewhat surprisingly):

1. Apps that saved session tokens still persisted (was still logged in to a lot of apps)
2. Probably for the same reason the session tokens were backedup, my downloaded Spotify songs also came along
3. I would’ve guessed that only iMessages would’ve been backed up, but looks like all of my SMS texts to android friends also got backed up which is nice
4. It did backup my iOS settings, I had sleeping screen turned off, and it was brought over

Main reason I’m asking is because I wasn’t sure if I should go through the effort of trying to revive the phone to get any obscure data off of it. In an ideal world I would get an exact copy. I’m OK just throwing it out otherwise

Not sure if anybody’s ever kept track, if there’s a resource somewhere out there that has a list, that would be great closure for me. Thanks!