It is recommended that you start with 10.1 before installing anything above it. You also need to remove the old version before installing the repo and new versions. I use sudo mysql_upgrade -u root -p to upgrade the databases. I start new Linux servers with the latest MariaDB version before installing anything else.
My suggestion is installing phpMyAdmin 18.104.22.168. It is an amazing tool that allows you to create databases and users in MySQL or MariaDB. I changed how it loads so it is accessed by the ip:port on the server. The port is not opened on the firewall. You need to be already connected to the server or using my VPN to access it. I created an sa account and disabled root access to the database server. root does have upgrade rights to MariaDB.