James,
Not sure what make it is yet. But I ChatGPT'd it and it was suggested thst I turn on a faucet to increase water flow along with the shower water. That works and the hot water stays on. Flow is low though.
Just spoke to some RV repair guys and they said to turn on the water pump to compliment the campground water flow and that should help. Haven't done it yet but I will come back to let you know.
Thanks
Tom