Bit late to make a comment, but as you like tinkering and it seems you're building this for gaming, why don't you just get the AMD 5800X3D cpu for £410 (it beats the 12900k in gaming on av) and pair with a decent B550 board). Pair it with your current 32gb 3200Mh DDR4 ram, either use your 1080ti or get a 3080/6800XT (should save £300-£500 over a 3080ti alone) enjoy the build to help scratch that itch, then with all the massive saving you made(well over 4 figures when taking mobo into account), splurge it on either AM5/6900XT/7900XT/4090 or Z690/raptorlake/4090/7900XT at the end of the year which will knock socks off todays build(DDR5 ram s/b faster/cheaper also hopefully)... todays build will still be high end and in demand, so wont loose your shirt when you sell it...
then you get to do 2 builds...
you never know, 1st build might calm the urge to build again, just get new gpu, flog 6800XT/3080, upgrade board for 14th gen/Z790 board or AM5 equivalent after kinks been worked out a year later