ok so, there's 2 ways to play 8K
one requires you to use your pinkies (index middle, ring, pinky)
the other one is all about using thumbs (thumb, index, middle, ring)
the native 8k mains normally prefer thumbs, as this layout grants you with more finger control and stamina, while also being able to hit all types of patterns hard to pull off with pinkies
as for the ranked section, the previous ranking criteria just considered 7k+1 as 8k, so most ranked/loved maps will play wrong cuz you're not using the correct playstyle. you can always check for the map's description and/or tags to check if an old map (usually from 2023 and prior) is using the 7K1S layout.
if you want a quick list of ranked native 8K maps, I have one in the 10K+ serverif you want non ranked content, you can check profiles like HeavenUsurper, krrcream or a ri su for some native 8K maps that are just hidden in the server
and for 8K VSRGs there aren't as many, really. Most I can think of is EZ2ON REBOOT R, which has a native 8 Key mode with a customizable layout (which, yes, supports the idea of playing 8k with thumbs) and project godhand, which even if its a mashing rhythm game, you can still be a nerd and play it like a normal VSRG.
Djmax is NOT an 8k game, its 8b layout is just 6K + 2 bumpers btw