Help topics say SUPER is required to bypass read_only

help ALTER USER

The ALTER USER statement modifies existing MariaDB accounts. To use it, you
must have the global CREATE USER privilege or the UPDATE privilege for the
mysql database. The global SUPER privilege is also required if the read_only
system variable is enabled.

help SUPER

SUPER
—

Execute superuser statements: CHANGE MASTER TO, KILL (users who do not have
this privilege can only KILL their own threads), PURGE LOGS, SET global system
variables, or the mysqladmin debug command. Also, this permission allows the
user to write data even if the read_only startup option is set, enable or