Steam

Not all Steam games use it as DRM. Many Steam games you can simply launch the executable without Steam installed and it will work.

Still, GOG is much better on that front.

But even games I buy on GOG, I often launch through Steam to take advantage of tools like Proton and Steam Input. Steam’s dominance stems from unwavering commitment to building a good user experience, and I’m not ashamed to reward that with my wallet vote.