I got the Cosmos a few days ago and been playing Arizona Sunshine and Beat Saber. Loving the experience without having to have base stations. I pre-ordered the O.G. Vive but sold it due to the resolution (and my PC at the time couldn't SS). I couldn't even read the text in Elite Dangerous and now with the Cosmos it's much clearer and great experience...
Well, back to the tracking. Beat Saber works for 98%, but sometimes loses tracking even though the controllers are on a 90 degree scale from where I'm facing. (Note, I just started with Beat Saber and very novice player that misses a lot just because I'm bad at the game).
One thing that NEVER works in Arizona Sunshine is when using the sniper rifle and needing to have one controller very close to the VR headset (but still in-front), it always loses tracking. Also having one controller in front of the other, the one furthest away from the headset loses tracking.
I think the issue in Arizona Sunshine (and I guess all other games with "2 hand 1 gun"-shooting) is the most important part of the tracking to fix. I even tried taking one hand behind my back with a flashlight in-game and it worked great - so gyro seems to do it's work fine.
Check this video, at 10:30, is what's never working at all with the Cosmos:
https://youtu.be/SJGMZYbDXPg?t=630
Tried with only one hand close to my shoulder and that just made the sniper rifle spin around like crazy.... in all 3 locations in-game where I found the sniper rifle. So it's the right hand of the guy in the video, that is not working with my Cosmos at all. I guess it's a general problem for everyone?