Hello!

MySQLTuner displays warnings and recommends various changes that are not relevant when servers allow only connections from localhost.
This includes warnings about hostname restrictions, SSL connections, and replication.
All of them should be hidden when bind_address = 127.0.0.1.

User 'user_name'@% does not specify hostname restrictions.
Restrict Host for user_name@'%' to user_name@LimitedIPRangeOrLocalhost
RENAME USER user_name@'%' TO user_name@LimitedIPRangeOrLocalhost;
Current connection is NOT encrypted! Consider using SSL for all connections.
Enable require_secure_transport to force all connections to use SSL.
Enforce SSL for remote users (ALTER USER ... REQUIRE SSL)
Set gtid_mode = ON to enable global transaction identifier replication.
Set enforce_gtid_consistency = ON to prevent unsafe replication operations.
Enable binlog_transaction_compression = ON to reduce replication stream size.
Enable source_verify_checksum = ON (or master_verify_checksum).
Enable TLS/SSL for encrypted connections.