It would be great if they contributed to open source projects like the Heroic Launcher, Lutris and even Wine and DXVK.

IMHO yet another store-exclusive (even worse if closed-source) sales + launcher application for Linux wouldn't really be a step forward for Linux.

I expect that anybody who doesn't have a fanboy relationship towards Steam already does or will if they just think a little bit, see that an open-source store-independent universal games launcher is way more free and open (and hence aligned with the Linux ethos and immune to enshittification) than any store-exclusive sales + launcher app.

As it so happens, given that freedom in gaming is GOGs unique value proposition, business-wise it's IMHO more advantageous for them to (very loudly and very visibly) support open source universal launchers (and maybe even some kind of open games store front protocol and open source implementation) and windows gaming adaptor layers (like Wine) serving a community with a higher awareness of the need for Software Freedom, than pushing yet another proprietary (even if open source) launcher that only works with their store - a seamless universal launcher is far more likely to pull people away from the Steam App than a GOG App.

Under such a strategy some soft marketing of in their store website promoting Linux Gaming Distros for Windows users and of promoting those universal launchers for Linux users, might help pull more people away from the closed-source store-specific application of their biggest competitor.