Leave it on the default character set. FWIW mine is utf8mb4_general_ci but I didn't explicitly set it when I created the database. What front-end is that?
MariaDB [flarum]> SHOW VARIABLES LIKE 'collation%';
+----------------------+--------------------+
| Variable_name | Value |
+----------------------+--------------------+
| collation_connection | utf8mb4_general_ci |
| collation_database | utf8mb4_general_ci |
| collation_server | utf8mb4_general_ci |
+----------------------+--------------------+
3 rows in set (0.001 sec)