There is no reason whatsoever to have for CREATE STATEMENT... RESTART WITH

This is not part of the SQL standard (a far as I know) and neither ORACLE or PostgreSQL has it.

If one wants to start the sequence at a specific value one should use START=
If one wants to set the value for an existing sequence, one can use SETVALUE()

By the way, when asking for a new feature, please describe in detail why this is needed and how it should be used. That information is critical in deciding if a feature should be added to MariaDB or if there is already a workaround that makes the request not needed.