most people use Ren'Py to make indie visual novels, as far as I know
https://www.renpy.org/
Its pretty simple to use im pretty sure, unless you want to do complicated stuff like battle systems or something
Also my post wasnt a joke xd I have thought deeply about this topic in the past lol not gonna lie, my idea at the time was a dating sim featuring all the top players tho
My suggestion is, for music you can probably use the actual songs that are in FFR (depending on the permissions I suppose, it seems like alot of people who give permission say its cool to use it anywhere).
Drawing the art might be difficult but might be funny and fun to do so it's ur call, might have to use stock images/anime pics from some site that allows free use for them, or commission someone to draw some art for it
Also my suggestion is to make minacious "meana" grace and pippi (the osu mascot) as villains lol, part of the plot could be them trying to ruin FFR by beating all the songs and making everyone leave the game
Also Bang Riot from Blastix Riotz as a villian lul