Well, we are not sure of the prices for the nest gen AMDs. The 6950xt is probably the best card to be had now. Certainly the 7xxx xt's will be a bit better, and maybe a little cheaper. I understand your eagerness, and a bit of a hard decision. The Vega can play some 2k games ok, but not many of the newer ones. 4k, not really. New has the 6950 xt MSI Trio and Sapphire Nitro for $999 and $1099.
I'd still wait. All the rumors hint at the new cards from AMD are going to be absolute beasts. You are so close now, you'll kick yourself if you don't wait.
Availability of new RDNA3 GPUs might be a disaster. You might need to wait another 1-2 years to get one. However, you can still wait until launch. If a new GPU is available and it's at a price you can afford, great. If not, both a 6950 XT or 6900 XT would still be available and most likely and even more reduced prices, so it's a win-win. Depending on game, assuming a completely GPU bound nature at 4K, 6950 XT is close to 160-200% faster than a Vega 56.
