Making a backup is one thing, if you're facing issues, you also have to restore it, and wipe the cache partition as well. I'm not telling you how to fix the issue, I'm just telling you how to roll back the changes so your phone is again in the working condition.
I see no reason why restoring a backup of a working system wouldn't bring the system to its previous state, maybe unless the ROM updated the vendor firmware as well and that's the culprit. Even then, depending on the device you can find an older version of the firmware and try it out instead.
I did all of that and anyway the phone boot and just show after restoring complete TWRP backup (ncluding firmware) home screen for half second before going black. Since other people are not experiencing it I am pretty sure it must have something to do with me not using lockscreen at all since pretty much everyone use it and that's the only difference I can find. Anyway in the end I did clean install, next time I will just use oandbackup and/or Migrate to save my time with restoring everything since even TWRP backup is useless.