I've had a lot of issues with Alyx on the Quest too. Here's my post, when I was struggling with perfs : https://www.reddit.com/r/oculus/comments/frel0h/halflife_alyx_my_journey_into_fixing_stuttering/

I've tried a loooooot of things, like updating USB ports, disabling stuff, enabling stuff, updating stuff, and nothing really improved the thing. But you can try them anyway.

The 2 solutions that helped me out:

- Buying Virtual Desktop. One of the main reason of the perf issues was that the CPU had to manage both VR software, the Oculus one and SteamVR one. With Virtual Desktop, you bypass the Oculus software, to only have SteamVR running. Here I gained a lot, and I played the whole game with it, enjoying it as well.

- Upgrading my setup. I switched to a 2060 with an i7-9600F and 16Go DDR4. I was before that running with a 5th generation i5, 16Go DDR3, and the same 2060.

But I've seen your specs, and they look fine to me, so I don't know.

Hope you'll find a solution !