[Q] Backup before bootloader unlock? topic

I am going to unlock my bootloader sometime next week (and root after that ofc).
I already used my phone for several weeks thought, I got it fully configured to my taste.

1. What exactly gets deleted when I unlock my bootloader?
All apps + usersettings + smses etc? Also everything in /sdcard ?

2. What is the best way to backup all data?
I can backup /sdcard alright, but is there a non-root app for backing up all apps + settings?