Solved!
So, I copied the files, as this comment reassured me
https://forums.opera.com/topic/52748/solved-how-to-copie-my-all-tab-to-another-pc/4#
I have noticed that I can't uninstall opera either and I can't find it in Program files, only in Appdata.
I just downloaded new installer and installed it and it automatically replaced the older opera(80.0.4170.63) and it is just running like nothing happened, with all the tabs and stuff. I have restarted the computer and it has been fine.
I will write again if I will have problems again.