I mould like to migrate from Mariadb 10.11 to MySQL 8.0 on CloudSQL service of Google Cloud with the less possible downtime. Has anyone tried that?

I am considering to add a vm with mysql 5.7 into the current replication as a first hop and then use the Database Migration Service that Google offers to move on to Cloudsql.
However, I am looking for any other options/ideas that haven’t thought about.