Your version MariaDB 10.3 is supported by CB 2.7.1, so it should install just fine.

But keep in mind that MariaDB 10.3 will soon be end-of-support itself, so I would recommend to plan for an upgrade at a different moment, later (after CB 2.7.1 upgrade).

Joomla (and we) don't officially support MariaDB: downloads.joomla.org/technical-requirements , although we try to maintain a compatibility, so can't give an advice on this, but here the releases compatibilities according to MariaDB team:
mariadb.com/kb/en/mariadb-vs-mysql-compatibility/
mariadb.com/kb/en/mariadb-releases/
and releases:
mariadb.com/kb/en/download-latest-releases-from-mariadb-corporation/