Can steam and gog players play together?

Yes, 2% of all steam uses Linux (including steamdecks)

I’m confused why you think only 2% of steam deck users would use Linux when it’s the OS that ships with it. Unless I misunderstood what you meant by SD?

I miss having a notification LED. It used to be super common to have a “breathing” effect with a given color when an app had sent a notification.

So a Snapchat for example would show the breathing as yellow, etc. Super convenient to check for messages without going and grabbing the phone.