@NostalgicNetwork
what are you talking about? Plutonium Discord mods rarely ban anyone. They are pretty lenient when it comes to the tons of people that repeated break the rules and discuss forbidden topics...
I think you are confused with the couple of GAME servers that ban whenever they want for no reason... that happens a lot.
I think the reason why Steam Decks could be banned is because they don't have some anticheat runtime, like Valve provides for EAC and Battleye. That's my guess as to why.
It's unfortunately been an issue for years - I've tried everything as well, including old method from years ago on this forum. For now there is no fix to issue, they even managed to get partial integration into Steam so the devs almost certainly know - hopefully one day someone finds a patch.