Can we use Redis Database instead of Mongo and other DB ?
As far as I know there is not persistence implementation for Redis, only the databases with scripts there: https://github.com/flowable/flowable-engine/tree/master/distro/sql/create/all plus Coackroach DB (https://blog.flowable.org/2019/07/11/getting-started-with-flowable-and-cockroachdb/) are supported.