Some of our client's faced noticed that cPanel installing mysql 8 by-default on CL8 installations. Unfortunately, if you wanted to stick with MariaDB , that's creating an issue - migration from Mysql 8 to Mariadb 10.x is not possible due to a difference in system tables.
Official article here:
Some info about incompatibilities:
As for what can be done in such a case. If that's a new server, your best way would be - cPanel reinstall with mariadb. To do so, proceed with the following steps:
1. Reinstall OS.
2. Create a file /root/cpanel_profile/cpanel.config
3. Add desired mariadb version to the file, for example:
4. Proceed with cPanel install:
cd /home && curl -o latest -L https://securedownloads.cpanel.net/latest && sh latest