H2 vs HSQL vs DERBY for small amount of users in production

Hi all;
I am in a situation I am constrainted to an embedded java DB for keycloak.
the keycloak docs state that H2 is not recommended for production but it seems that this is related to synchronization when stress on the DB is executed (which is not my case).
i am developing an intranet app with no more than 10 users that login to the system to get a token so i feel in this case H2 can be ok. am I correct?
also, should i even look at HSQL/DERBY with my kind of app as an alternative?
thanks.