Upgrading Truma gas heater

Hello to everyone. First post.

I have a Truma S3002P gas only heater. It is well past it's sell by date.

I would like to change it for a heater with a gas and electric option. Can anyone recommend what heater to buy to facilitate this?

I imagine that a combi or warm air replacement option would be major aggro?

Sorry if question is simplistic. I have just started motorhoming and am learning.

Thanks