Hi there and welcome!
If you are positive the controller is out (which is like top 1 or 2 reason an MES dies) then you could do a very simple rewire job on the MES and hook a PID controller to it!!!
You will end up with a better smoker that you can keep running through anything short of it being hit by lightning lol.
With an Auber PID controller you will likely be able to keep within 2 degrees of your set temp. No more big temp swings or inability to hit a true max of 275F in the MES.
One tiny tiny "con" is that you must now use an A-Maze-N Pellet Smoker (
AMNPS) to generate smoke but that really isn't a con since pretty much every MES owner uses one anyhow

If you have the
AMNPS you can cold smoke with your unit whether you put a PID controller on it or not. I always recommend a mailbox mod with the
AMNPS for greater smoke control and flexibility but some guys roll without it and cold smoke anyhow.
Here is my post on how to do an MES rewire to add a PID controller:
https://www.smokingmeatforums.com/threads/mes-rewire-simple-guide-no-back-removal-needed.267069/
I hope this gives you some ideas on what you can do with that MES unit and as you can tell I'm a big fan of doing the simple rewire and hooking a PID controller to them to have an ever better smoker than what
masterbuilt puts out brand new :)