Game not launching via steam

Hello all,
today I downloaded the BeamMP multiplayer mod. After the first few rounds I can definitely say that the mod works very well, but I noticed one thing that can’t be considered a bug, but gave me something to worry about. When you start the game via the multiplayer launcher, the game is still shown as “off” on Steam. Is that not a crack? Can’t Steam (Valve) punish you for that? What I mean by that is, you bought the original game on Steam, but you use an .exe modified by third-party developers, which then allows you to use the game without Steam. Or am I wrong? I’m also active in other forums that don’t deal with BeamNG, where even a modification to the .exe of the game is called “dangerous”, for which you can possibly, and with a lot of bad luck, get a Steam exclusion. But now you even have a launcher that apparently starts its own .exe, which is not recognised by Steam. Isn’t that against the rules?

Otherwise, it’s really great what you’ve done, keep it up!

Best regards,
BlackyTrains