IMO yes. It's all been said in the thread for it (don't forget with the code it comes down to £649, and has two games) but the XTX is not $999. Or £999. You are forgetting about 20% VAT. So the cheapest it will probably be is £1200. If you can get an AMD reference one, because literally every other card is sure to cost more.
That means the 6900XT Asrock works out at nearly half the price. The XTX? 100% will not be twice as fast. The 4090 is what? 55% or so? faster than the 3090Ti. If the XTX was twice as fast and thus worth twice as much £ per frame? Nvidia would be in very deep doodoo.
It won't happen. So you then step down to the 7900XT. Which will be £899, plus VAT. You are still over a grand. And that isn't for an AIB card either.
The 6900XT for £649 is the best value card I have seen in years. Many years. The 1080Ti cost about that much when it launched IIRC.
Right now? nothing needs a 4090 unless of course you are running silly resolutions with silly features. Silly because you will be playing 1 year old or older games on it, none of which are all that.
New cards never, ever offer the best value. No brand new tech does. Not ever in all of my 49 years on this earth have I ever been wrong about that. It's just like new cars, etc etc.
BTW talking of value. IMO? the lower tier to mid tier cards right now represent the worst value. Because people are losing their minds that you can pick one up at RRP or a little under it ! that's nuts. The 6900XT? was a £1000 GPU. So that means you are absolutely smashing the RRP by a considerable sum.