(1064) syntax to use near

... And before there was no such error.. now you can't set the tables through the GUI.

FLUSH PRIVILEGES; SHOW COLUMNS FROMmysql.user; SELECTuser,host, IF(LENGTH(password)>0, password, authentication_string) ASpasswordFROMmysql.user; SHOW GRANTS FOR 'root'@'%'; SHOW CREATE USER 'root'@'%'; /* Ошибка SQL (1064): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'USER 'root'@'%'' at line 1 */

That may be happening on a very old MariaDB servers. Which server version is that?

10.1.48 I had to manually issue the rights to the table with the command :(

Yes, because MariaDB had larger changes in their user management commands. HeidiSQL supports only the newer ones. v10.1.48 is from 2020. I would recommend to upgrade.