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?