Cannot connect to WP DB

HI, coming in with a backup from cpanel, I cannotr make the WP sites work…
in the importer I set the UN and PW for account and get database connection error"

Makes sense to me, since the DB PW set in wp-config is another … so I try to set the DB_USER password in the (very confusing) database interface of Virtualmin, but cannot make this connection error go away… I by now tested every pw I can get hold of…to no avail…

When importing, the database_user (Mysql 5.7)) should have the same name and PW as on old server (cpanel)

Importing into MariaDB 10.4, and my admin made one imported site work … somehow,

He is not available right now and I want to get on… but this error make me rip out my hair

Any hint? And is it me or is the Database “area” much cleaner and easier in cpanel?
THx
Dan