Good call, do keep us posted with your results on that mate. Been very intrigued with Intel's gpu's since they were announced despite them being a gen behind now, they seem pretty good value if you can get one close to MSRP.Pairing it with the experimental A770. You would have to wait for reviews, it would likely help with the 4090/4K. Although, if money is no object then why not.
I'm running a 3090 so it might help it stretch its legs that last little bit. No need for a 4090 as im on 1440p UW, the extra cpu power would help i think.