i guess I can share this story here, as kind of a recap/another potential plea for help as to a somewhat bizarre issue I had a while ago (that I wrote a full blog post about) when I bought one of those official Konami Entry Model IIDX controllers - not a PS2-era KOC, but the newer ones with a USB port - that I realise not a lot of people actually reccomend since like... it's not like they're outright bad, necessarily, but you can get a much better one with arcade parts instead of membrane switches for not that much more, but, eh, i wasn't entirely sure if I was comfortable ordering from gamo2's site at the time to get an FPS like I was originally considering, and I was also concerned about noise levels since arcade switches/buttons are apparently pretty loud. frankly, I was pretty sure that the people saying that they were terrible were exagerrating, but as a complete beginner it'd likely be good enough to get me started regardless. so, this is what i ended up getting.
the problem though is that once I got it, it turns out that there is seemingly some kind of incompatability between my PC and this controller. it just refuses to work when I plug it in, which is extremely weird. it's recognised, and if i'm lucky I might get like.. half a second where it will actually register inputs, but for the most part it's just unresponsive. interestingly, it did work on a random laptop that we have, and I could get it to partially work on my phone (turntable worked but buttons didn't, i presume due to not getting enough power?). so that was pretty weird.
the most probable explanation i was able to find was from someone in a discord I was lurking in who had the same problem, and suspected it could be an AMD issue? from my limited testing I can seem to corroborate that explanation. it didn't work on my Steam Deck either (which I know is AMD based), and the laptop it did work with was Intel. given that my main PC is AMD that's obviously a bit of a problem lol
i found a tweet from the same person who mentioned this that their controllers worked in a virtual machine, which lead me to my current workaround, where whenever I want to play BMS or whatever, I just open a linux VM in VirtualBox, and then i have some Python code I wrote that starts a TCP server to bring the controller inputs sent to the guest back out to my host machine using a ViGEmBus virtual DS4, which does at least work and allows me to use the controller on my main PC. but it seems like a pretty flimsy solution, it's somewhat inconvenient, and i'm not sure how much input lag this is adding - though I tried to test it with Etterna's offset calibration tool and it didn't seem like it was adding much, if any, extra latency, but it'd be nice to have the peace of mind, you know? (plus, not sure if this workaround will work super good with IIDX Infinitas if I ever do decide to cough up the money for that).
i eventually ran headfirst into the infamous ryzen USB stability problems from buying an external sound card, and since I was too lazy to update the BIOS I just used the PCIEX16 == GEN 3 workaround for the time being - I was wondering if this was the potential source of the problem but while it did fix the issues I was having with my sound card it didn't do anything wrt. the IIDX controller unfortunately, so I guess it's not that. i would try a USB 2.0 port since I know sometimes 2.0 devices on 3.0 software controllers can cause problems -and given that it works with VirtualBox's emulated USB controller, that might be what's happening - but my motherboard doesn't have any USB 2.0 ports. i've wondered if a USB hub might change things but I didn't have one on hand to test and I'm not really about to just go randomly buying hubs until one magically decides to work
anyway, I do at least have the thing working now as I mentioned but if possible I would like to figure out a more permament fix. i know it's just a generic USB HID device so I'm not sure if there's any updated driver or something that I can download? admittedly, i've not actually looked. but uh... if anyone comes across this post and has any ideas for a potential solution, feel free to hit me w/ 'em