A 3060 is really the minimum that I'd personally be looking at, though this will HEAVILY depend on the resolution of the VR headset that you would go for, a Pimax, G2, Vive Pro 2 will seriously struggle to maintain a 90 with a 3060 unless you drop the resolution to below 100% which would make the image quality really horrible.
AMD cards could be an option too, however even now I see reports of them having issues with running VR smoothly, so just to be safe I would just stick to NVIDIA for VR.
Now as for the VR headset, Half Life Alyx is best experienced with the valve Index controllers. You could buy the whole Index kit if you can spare the money to do so, but you could also just buy the base stations and controllers separately, and then get something like a Quest 2 for the headset. Just remember that setting up an inside-out tracking headset like the Quest 2 or G2 Reverb with base station tracked controllers like the Valve knuckles can be really scuffed, and I would
always recommend hardware that is natively made to work with each other.
I have no idea what your budget would allow for, but here are my VR hardware recommendations for Half Life Alyx:
Cheapest, will probably cause the most issues:
-Meta Quest 2 /w Link Cable
-2x 2.0 Base stations (Cheapest available are sold directly on steam)
-Valve Index Controllers
Most convenient but more expensive:
-Valve Index VR Kit (Will come with everything you need when it comes to VR hardware)
Worth taking a look at if you don't mind the used market:
-Vive Pro 1 (Depending on the kit, this may or may not include base stations, I recommend against settling on the Vive Wand controllers)
-2x 2.0 Base stations
-Valve Index Controllers
As for you actual PC hardware, I'd recommend:
-RTX 3060 or better (Preferably stick to NVIDIA)
-Just to be safe, a better power supply with a bit of overhead, I'd probably be looking at 750w+
Use this to help guide your choice:
https://cultists.network/140/psu-tier-list/
- A Ryzen 5 5600, it would help performance in general and it's amazingly priced right now, but beware that you would probably need a BIOS update.