Unless money is of no object to you I don’t see the point in the 3090. All the benchmark tests I’ve seen give it about 10% advantage over the 3080 and unless you’ve very lucky its about £700 more. If you pair a 3080 up with a good processor you’ll get similar performance for quite a lot less money. If 4K isn’t essential then a 3070 or 3060ti paired with a good processor is a good buy at this point.
I’ve got an overclocked 3080 paired with a Ryzen 5 5600X and from what I can see any performance gains at this point will be down Asobo optimising things better rather chucking every more expensive hardware at the problem. My VRRAM is not maxed out with my 3080.