Definitely some tips on latency would be an absolute must for any guide on rhythm games because they live and die on how well the audio, the video, and the player are all synched up. For reference, I first played Hi-Fi RUSH on a setup that had a little bit of audio latency. It was still really fun, but I couldn't really get the hang of staying on-beat through the whole thing (though being distracted by talking to my co-commentator probably also didn't help).
Then I played on a setup that had no (or at least much less) latency and wowee-zowie I was nailing Just Timings and parries and started rocking through Hard Mode like nobody's business - I was even able to beat Kale on Rhythm Master fairly easily, which was very satisfying after he killed me a billion times on my first playthrough, ha ha ha
So yeah, latency is a big deal - whether it be because you're using an audio processor like VoiceMeeter or playing through a device like an Elgato and viewing in OBS, even the tiniest amount of delay can throw the whole thing off and make the game close to impossible.
A good guide for importing songs into Dead as Disco would be pretty cool too but I think there's plenty of resources for that