Yesterday I changed appearance through System Settings → Appearance. Downloaded some themes and some other related stuff. After a while I couldn’t open System Settings, so I removed systemsettings package and installed it again. After reboot my bottom panel(the one with menu etc) dissapeared and also I can no longer open systemsettings5 in console(other programs seem to work through console).
You probably broke your system, removing one of its core components and everything requiring it. See this thread here this is the same problem… Manjaro after update error Problem being user removing core components.
Who knows how to change theme via console? Maybe this will help. Or removing the most recent installed themes and related stuff. Appearance factory reset? I am pretty sure I downloaded broken theme or something, cause I couldn’t open System Settings way before removing it. I don’t know where this stuff is located.
Interesting. How about doing similar thing with my backup? I have not so fresh backup of my entire disk(last backup December last year). Will it be better to do this with backup?(in terms of losing configs).
Ok, I finally restored my old panel without using the command suggested by @Strit (so scary).
What I did:
Renamed all files in ~/.config/ starting with plasma- to plasma-replaceaccording-OLD, and then copied all files from my backup starting with plasma- (plasma-localerc, plasma-nm, plasma-org.kde.plasma.desktop-appletsrc, plasma.emojierrc, plasmanotifyrc, plasmarc, plasmashellrc) to ~/.config/ and then restarted. It was important for me to have it back since I had Sticky Notes widgets with useful information in them.
Try it on your own risk!
If you ever come across the same issue and you are also noob as I am don’t install those packages(plasma-desktop etc. as dependencies to systemsettings) as after system upgrade they’ll become orphans and after you delete orphans the panel disappears again