I have not had issues with Horizon 5 or the new Forza on my steam deck under Windows 10 LTSC 2021. I believe I played both at or near launch.
That is the first I have heard of a game not working on LTSC.
Edit:
My timeline is off, I did not try Horizon 5 on my steam deck until about a year after it came out since Horizon 5 predated the steam deck.
However worth pointing out that it is one example of a game not working on LTSC vs many examples on proton so I would argue it still Wins out on compatibility.
I have not had issues with Horizon 5 or the new Forza on my steam deck under Windows 10 LTSC 2021. I believe I played both at or near launch.
That is the first I have heard of a game not working on LTSC.
Edit:
My timeline is off, I did not try Horizon 5 on my steam deck until about a year after it came out since Horizon 5 predated the steam deck.
However worth pointing out that it is one example of a game not working on LTSC vs many examples on proton so I would argue it still Wins out on compatibility.