Restore backups/import without MySQL resetting mysql passwords?

I am sorry if it is somewhere documented in a noob friendly way, but i can not find it, found a few technical articles which i do not understand.

My target is very simple.

Yesterday i installed WHM and i have Mysql version: 5.6.37, i changed nothing about mysql. My previous WHM server (on which i made cpanel full backups) has version 5.5.57-cll

Now during restore (WHM/Backup/Backup Restoration) it says:

Please which commands to execute on my new server so Backup restorations does not complain about bad passwords and mainly do not change the passwords during restoration?

If i need to upgrade/downgrade mysql, then how exactly please, i do not have any special needs, what i just need is that restored cpanel accounts works and the mysql passwords are not changed. Or if change is necessary then any script or command that would sync mysql pwds with pwds in files.

Moreover i have many cpanel accounts and i found no way to restore full backups in a few clicks, I have to click maybe 600 times.

I restored full abckups, but mysql user passwords was resetted (randomized as above seen) and now i need to somehow replace mysql data by ones in abckups and without mysql passwords be reseted for users.

i already have all-databases.sql file which i can import, but unsure if that will work and be compatible with files. I am quite stuck and my all sites are down now.

Please kindly give me commands or exact steps to solve this. I do not understand technical things. Thank you very much.