After re-reading your post and thinking on my own issue if the new filter/fresh gas doesn't solve it there are only a couple more potential issues I see at least:
-clogging/partially clogged fuel lines
-Igniter/coil packs-seems far less likely as pumping the gas seems to get it started
-Fuel pump assembly unit. I have a 2017 teryx4 LE almost 900 miles. The fuel gauge stopped working and all grounds/wires looked good. I didn't check the connection on the back of the display because all other functions displayed properly. Figured Id google the fuel pump and its a float, pump, filter, sender unit all in one and $670 for mine. Called the dealer and THANK GOD its covered under warranty but its being replaced this Saturday morning.
Another thing and again could be just me. I don't feel the overheat experience is directly causing your issue. But, if your valves are out of wack from never being adjusted and the heat it would run better as its allowing the correct in/out time/volume for peak efficiency. Its controlling in a sense the in and out of intake and exhaust so if they are not opening enough/closing at the correct amount it just complicates things etc so again more of maintenance idea at your miles.
Keep us posted.
Orange 17 Teryx4 LE, 4.5k winch, Full windshield, Roof, quadboss front rack, full size front spare tire/wheel