For anyone wondering the music is by TAM music factory.
Most arrangements used in game can be found on youtube with the rest of Project Kats OST Here:https://www.youtube.com/watch?v=_GDzZsCsRk0&list=PLDOjCqYj3ys3g39aaq6IMgQao4ioMs7Bl
I have linked some of the more predominent artists work and the rest can be found on spotify/youtube
TAM music factory - Title screen music / Cloudy skye
here:https://open.spotify.com/artist/4eNKadh2oMaXiQqgZtN6Yt?si=cuWw52fiQfyitSIp5QGi1A
Hirokazu Akiyama - Unwelcome guest / Strange Ritual
here:https://www.youtube.com/channel/UCNPMwbX6-SclEmvFX5_ihCw
and here: http://www.hmix.net/ (the site is in japanese so i recommend the above link if you are unable to speak or translate conveniently)
Amacha / Music Atelier Amacha - Dangerous game/Midnight Music Room,
here:https://amachamusic.chagasi.com/ (japanese) no other platforms i can find him/her on as they seem to be very obscure.
M-ART- Kats theme/ Cheshire cat laughing
here:http://mart.kitunebi.com/ (japanese again) again very obscure
t12ya or @ DOVA-SYNDROME- Club room theme/Rocked by the city(?)
here:https://www.youtube.com/playlist?list=PL2vyqKNLXiUo7BefUvCou8K2P1_Doq_Ef
or here(???very obscure...):https://dova-s.jp/bgm/play11578.html
HOPE THIS HELPS!!!