The part that confuses me a bit is that it’s a mod that removes functionality from a single player game. Usually features get added, not removed. When something is removed it’s usually to improve stability or performance. Or to rebalance the gameplay. This change falls into none of these categories.

Well I guess if the mod author did it to garner attention or make a point he/she/they succeeded.

Open Dyslexic has you covered. It was designed by experts for this purpose.

Take a different approach: look for players also playing the same games as you. So find a community for your favorite games, be it on Discord, a website or here on the fediverse. Why would it matter specifically that they are using a steam deck? Steam Deck is treated as a PC if you are specifically worried about cross platform play. Conversely even finding others who also use a steam deck means little to you if they are into completely different games and genres.