Tuning remote connection PyQT5 to Mariadb-Server 10.5 on Debian Bullseye

Tuning remote connection of PyQT5 to Mariadb-Server as well as to MySQL seemed to me the most time consuming part of this small project. Obviously, the options for Mariadb and MySQL are mutually exclusive.Tuning network configs on bare metal described in details utilizing `netstat -ant | grep 3306` output required to verify that connection is established.