Are Steam Deck runs allowed? And if they are, would they count as a PC or Console run?

steam deck is UMPC(Ultra-Mobile Personal Computer), so I think it counts as PC.

Steam Deck runs the Steam version of the game, therefore it would be PC for now. However I'm not actually sure if Sonic Frontiers has its own "build" specific to Steam Deck or if its a compatibility layer, please let me know so I can add SteamDeck as on option.

Sonic Frontiers uses Steam's default compatibility layer, Proton

The load remover doesn't work under Linux, so you would be forced to use RTA for timings