I found this sales video from etrailer
https://www.etrailer.com/tv-Demo-Fur...FGH4ZSASS.aspx
Looking at the video - the stove top unit is separate from the oven with no hard connection...and when you read the installation instructions from the Furrion manual (pic below) - I think the top unit is simply pressed down into the countertop cutout with butyl tape...no screws. I would get a putty knife or flat head screw driver and work my way around it to pry it up.
I did not see any info on adjusting the flame. My home propane stove has flame adjustent screw down in the knob stem - but the Furrion does not have that. I checked.