I don't really have this issue because I use my desktop as a sort of "I have these" list with various games' shortcuts, but I can see how you'd forget about these games if you don't have them right in front of you.A big problem for me with non-Steam games (GOG, EGS, Battle.net, Uplay) is that because I am logged into Steam all day (I use it as my main platform), I forget games that are not on Steam. Like I got Bugsnax, Pathless and Godfall which are on EGS on wednesday and thursday, I bought Valhalla with the price error (still no order confirmation lol) on Uplay and I got CoD on friday.
I haven't touched any of the EGS games or Valhalla since thursday and CoD since friday, I forgot I own them. Because I don't regularly open those launchers (I call them launchers while Steam is a platform) in compared to Steam which I have always open. So I forget about games on them.
This is a problem for Epic/Ubi/Acti.
Which brings me to that very important question : what in the world do you use your desktop space for then?