That isn’t known. It’s unlikely there will be changes that require human intervention, but we’re not calling it stable because things may still change (the RHEL/Alma/Rocky repos changed their structure a few days ago in breaking ways, for example).
Start new topics for new questions, but this question (mostly in reverse, going from MySQL to Mariadb) has come up many times in the forums. Search for it. It is possible and relatively easy (though not recommended…unless you have a damned good reason to change, don’t make your life difficult, the two databases are nearly identical from a user perspective).