Need help mariadb optimization for performance configuration
default-storage-engine = MyISAM


Better to be in InnoDB.

You currently have 19GB of InnoDB data, but no setting for innodb_buffer_pool_size?  That VARIABLE should be perhaps 70G for that server.

To dig deeper, let's get a more thorough analysis of variables, plus look for slow queries.  See http://mysql.rjweb.org/doc.php/mysql_analysis