Mariadb replication - Ignore users changes

I need to set up multi-source replication (3 masters and 1 slave). Since all masters have users with the same name but not the same rights, I'd like to avoid replicating users' changes on the slave because it breaks replication.

I've followed this : MySQL Replication failing on `mysql`.`user` changes but it didn't seem to work.

I've tried different configurations but none works.

• Ignore table mysql on the slave :

replicate_ignore_db=mysql

• Ignore table mysql for each connection on the slave:

master1.replicate_ignore_db=mysql
master2.replicate_ignore_db=mysql
master3.replicate_ignore_db=mysql

• Ignore the mysql table in the master's binlog :

binlog-ignore-db=mysql

I'm working with Mariadb 10.6 on Debian 9. The master's binlog format is ROW.

I'm still getting errors in the replication regarding users changes. How can I make the replication ignore the users' changes ?