Check for a clogged vet in the fuel cap. Try loosening it and running the tractor as you were doing. Check for loose fuel hoses sucking air. Check to see if there is dirt / debris in the tank. Depending on the age of the tractor (in 2020 LS started to use an electronic throttle control), it could be that controller if present.
I am assuming it is no longer under the bumper to bumper warranty..... I think the fuel delivery system is under the drive train / emissions warranty.
Good luck finding the problem!