OP, I was in about the same shoes, although my reasoning for upgrading was a bit more selfish - my RTX 3090 was 3 years old and I wanted it gone. The RTX 4080, if you can afford it, is an extremely efficient and outrageously powerful graphics card with very good drivers and excellent overall compatibility. Couldn't be happier with mine, although I have a particularly awesome model (and extremely expensive one too). This GPU is around 40% faster than the vanilla 3090 at the stock power limits at half the median power consumption. Should still be a good 20 to 25% faster than the RTX 3090 Ti, which is still an insane graphics card as far as I'm concerned. The 16 GB is not and will not be an issue even at 4K.
If you need something a little cheaper, the 7900 XTX is also an excellent card, although AMD's drivers are
very hit or miss on stability and compatibility fronts, and should be considered an afterthought if you're after the latest graphics technologies around. Unfortunately, with AMD, you never get the state of the art experience, whether due to performance shortcomings or things just being flat out unsupported, and it's not a matter of whether you may have problems, it's
when you will. Some people will never run into problems - or at least not enough to actively acknowledge that they're there and that this mars their experience, others will dread the day they decided to purchase their card (and you can guess the camp I hail from) - meanwhile, Nvidia's graphics drivers tend to be "boring", the exact way you want them to be - you'll often forget you haven't updated them in weeks.
Surprised to see so many people recommending the 4080. I get its not a half bad card but the price its just insane, and its not even close to the 4090 in performance. Its an insult, and buying it only convinces nvidia 80 class cards at $1200 USD is acceptable.
It's not that far off. The 4090 is more powerful, yes, but the 4080 is a very balanced card which achieves excellent utilization figures at a rather modest power footprint. Its only negative is the high price. Agree with you as well, the 16 GB, 256-bit "4070" would be very welcome, in fact, I believe this is the true "4070" and the 4090 is what the 4080 should have been. Oh well.