I get a popup asking if I want to launch in regular, Vive/Index or Oculus mode. When I launch Oculus it says "Oculus HMD not detected" and closes. When I select Vive it launches but then no controls as you mentioned.

So, just for fun, I launched the game as a regular game, no VR. It worked fine. made it through a couple days, Nice. Graphics are really dated for a regular/contemporary game but the actual game play is fine. Its my kind of game so no issues there but VR sure wouild have been fun.

BTW, I too tried all those launch options and none of them worked in VR. too bad.

I am able to get it to run on my Oculus Quest 2. How I am running it, after I installed the game via Steam, I started up the Oculus PC Desktop app, then added the game to the Oculus library. I then started up my quest and went into VR (just on the Quest). From there, I started Oculus link from the Quest home, then once it connected to my PC, the Solus Project then showed up in my Oculus ink library while in VR. I then started it directly from there. Usually I set most Steam games to run this way and they seem to run better (though not all are friendly with this and require me to go all the way into SteamVr/etc). I might have also had to go back to my PC desktop and agree to "allow this app to change things on my computer" thing or something like that. After that I put the headset back on, then waited a number of moments and it loaded in VR. I was able to play it from that point.

Thank WildCat for posting your solution.