t’s the same as Steam, you sign the contract called “ User Agreement” that has a section on how you don’t own the games

this is what you said,

Steam is a platform, that host various games, some with DRM, some without DRM

Valve is a dev, their games have DRM. Just because Valves games have drm, doesnt make that all games on steam have DRM. You painted an entire platform as DRM when it isn't. it's one thing to say that Valve theirselves puts drm in their games, its a completely different statement to blanket all of steam to be drm, when thats a completely false statement.

For example, go get someones steam copy of witcher 3, youll quickly find out that it itself has no drm, despite coming from steam, and not the GOG version.