I'm looking for a way to use FCEUnext instead of Nestopia.
Kid Dracula refuses to run on Nestopia (it's a known issue), therefore FCEUnext is my only option. This known issue is also present in several Japanese titles, especially when it comes to Konami.
I don't understand why only Nestopia shows up, while Recalbox's wiki contains details on so many libretro cores. Generally speaking, FCEUnext is a better core.
https://wiki.recalbox.com/en/emulators/consoles/nintendo-entertainment-system/libretro-fceunext