Hello,
The Mautic requirements page states that mariadb 10.2 is the minimum as of today.
https://mautic.org/mautic-requirements/
However the developers have suggested today that mariadb 10.11 or even 11.x should be the minimum to run Mautic. See the following post.
https://forum.mautic.org/t/mautic-7-0-alpha-mariadb-supported-version-10-11-x/36285
I wish I had know that six months ago.
Thanks.