The Valentina Studio team has tested Valentina Studio with Maria DB's SkySQL "Database in a Cloud" service and found that Valentina Studio works quite well. SKYSQL is a pay as you go hosting service.
MariaDB is based on MySQL and supported by Valentina Studio, Valentina Reports ADKs and of course, Valentina Server (for both Valentina Reports Server and Valentina Forms). You can also use Valentina Forms as a front end to a MariaDB server, including those hosted on SkySQL.