https://www.tecmint.com/mysql-mariadb-security-best-practices-for-linux/

https://mariadb.com/docs/deploy/best-practices/

Feeling at odds dedicating resources to MariaDB certification, when there’s other platforms with Exam options on Pearson Vue.

https://www.businessnewsdaily.com/10734-database-certifications.html

Depending on the demand, this may vary. MariaDB is quite prolific in the web hosting space at time of writing.

Redhat have a clean, comprehensive guide to MariaDB deployment.  

https://access.redhat.com/documentation/zh-cn/red_hat_enterprise_linux/8/html/deploying_different_types_of_servers/using-databases