Has your OS ever refused to install the MariaDB client package or the MySQL client package due to a conflict with the other?
It feels like it should be possible to have both, but unfortunately I have yet to see a solution for this.
For a subset of these cases, all that you want is just to have the client tools such as the mariadb/ mysql CLI and the mariadb-dumper/ mysqldumper backup programs co-existing on the same OS. (I.e. you don't care about the static/dynamic libmariadbclient/libmysqlclient libs etc).
So, I decided to write up my solutions for this:
https://dbdemon.com/installing_mariadb_and_mysql_clients_on_same_unix_host/