I have almost identical system specs as yours except for 32gb Corsair ddr4-3600 and an EVGA supernova 850 psu. As much as I'd like to upgrade to a 3080ti, this system no slouch by far. Great for the Index.

As for Index accessories, I'm quite happy with my decision to get the comfort kit by StudioForm Creative VR(https://www.studioformcreative.com/product-page/index-200-gram-7oz-enthusiast-kit).

I found the Index to be a bit front heavy and causing fatigue and discomfort by resting a bit too much on my cheeks. This combo kit includes a counterbalance weight that velcros to the back of the headstrap and another strap of material that helps distribute weight across your forehead. Because of how it distributes the weight, I find that it actually makes the headset feel lighter on my head overall. It's on sale right now for only $33US so it's almost too cheap to not try out for yourself. I'm in no way affiliated, just a fan of the product.

As another has mentioned, if you do wear glasses then prescription inserts are a must. VROptician and WIDMOvr. I've tried both and I actually prefer the ones from WIDMOvr for various reasons, but they are both fine. I could provide more detail if interested.

You can find a few different charging docks out there like this one on Amazon(https://www.amazon.com/AMVR-Controllers-Charging-Functions-Controller/dp/B08MVQCSV5). I have one similar to this one but an older design I think. It doesn't have a single USB cable with built-in charging controller chip or a hook for hanging your Index like that one does.

The only other real accessories for the Index I can think of are for the frunk, like a fan module. I've never ran into heat issues myself and felt the need for one. I'm also wary of blowing outside air into/through the hmd as well as I once had to RMA my Index after a spec of material somehow got inside and stuck on one of the screens after I used a can of compressed air to clean the lenses once. Valve support was awesome and sent me a new one quickly, but I've heard that it's a no-no to used compressed air now. I don't recall hearing reports of any issues from people using a frunk fan, but could be a risk.