PItts Special S2S beeps and then dies, and has very little power at take-off. Constant beeping

It could be something with control mapping, but I have mixture at 100% and throttle all the way full, prop set various places, but mostly away from feathered (no power there!) and yet it barely gets to takeoff speed, starts beeping as soon as the wheels leave the ground, and then 15 seconds affter takeoff it loses so much engine power that it basically stalls and then falls sideways into the ground.

The beeping sound is not associated with any engine failure or status light on the onboard screens or cockpit gauges.
I suspect a control mapping issue causing the prop to inadvertently feather but I’m not seeing the prop come back to feathered.

If you are hearing a quick beep beep beep, I get that as well.
I don’t get a lack of engine power though.
I have noticed you have to trim down a lot on lift off, it climbs like a rocket and looses speed very quickly (in seconds) if you don’t.
Could that be the issue?
If not, is there any changes in the engine gages to determine what happens?