Andy Guibert (IBM) is creating a reactive driver to access DB2, based
on the VertX APIs.
The new driver is not fully complete yet but I believe it might be in
good enough status to experiment with its integration in Hibernate RX.
An overview of its status can be found here:
Andy has been contributing on Quarkus as well: don't hesitate to reach
out to him for any need, as I hope he'll be able to help on RX too.