At least that money would give more future proofness in 3900X than in 2080 Ti.Genuine question. If your main use is mainly gaming and general use, then is the extra money you are spending on a Ryzen 9 3900x and Gen 4 RAM worth it? You will see almost no frame rate increase or loading speed advantage by going that route.
If you have the cash, I would definitely stick with the 2080 ti GPU or whatever is the best at the time you make the leap. But I would seriously consider spending less on the CPU and RAM. Something like the Ryzen 7 3700x would be plenty, and Gen 3 RAM would give you the same performance and save you money. You could then also go for a B450 or 550 motherboard when they release, as again the benefit of a 570 motherboard is quickly diminished for just gaming.
12 core will shred through games for long time without minimizing background software.
While that only 35-40% faster than full £1000 cheaper Radeon 5700 XT 2080 Ti will be shredded in performance in year or two.
Even next Xbox won't be that far behind it.