the speed settings are 30 to 100 and im running at 30. i do have a gate valve on the return pump and thats turned open all the way.

can that be affecting the fluctuating water level?

So the gated drain is running a full syphon?  (completely full of water?)

If the water is gradually increasing in the display, it implies the water is not draining quickly enough.  I would try either opening the gate valve on the drain very small increments OR closing the gate on the return pump in very small increments.

when gated drain is fully open, return pump cant keep up, which is why i keep return pump valve open fully and main drain valve closed to trickle emergency drain. ive only been adjusting main drain valve a milimeter each time but it seems even that much of a turn makes a big difference. should i try adjusting valve on return pump once i think im as close as i can get to a water balance in the overflow?

thats a good idea. ill do it when i have more time. right now i managed to tune it so it only drains every few hours. when it does drain, it eventually balances out again. throughout the night it only drained once at midnight but luckily thats when i went to bed so i think the rest of the night it went quiet unless i slept through it haha. maybe i just need to tune it right im just not getting it right each time.

It's a bit like a car engine ,sometimes needs a little bit of fine tuning,
Dave
 

Rather than just valving the return , teeing into it and valving the branch back to the sump can help with minor adjustments, I use the valve on my UV pipe run from the return pipe back to the sump for my minor micro adjustments .

huh thats an idea. ill keep it in mind. when i was struggling to balance the water level, my return valve was turned all the way open so i have room to tune but will keep this in mind. thank you!