I think your build looks nice, however a 4090 would not be strangled by the other components in your build.
i7-8700k 700:-
ASUS GeForce GTX 1080Ti ROG Strix 2500:-
NZXT Kraken X62 300:-
ASUS Rog strix z370-e gaming motherboard 300:-
G.skil 16GB ram 3200 300:-
1TB M.2 SSD 500:-
2TB Hard drive 500:-
NZXT H700i 1000:-
Seasonic Focus+ 650W 80+ GOLD 500:-
White sleeved cables ??:-
Total: 6600:- so with the sleeved cables and Windows around 7000SEK would be a fair price.