I finally managed to have it working, apparently the issue was the ROM region. I changed it to EU/PAL using "Advanced_SNES_ROM_Utility" and it run flawlessly. In case it helps :)
Thanks a lot for the suggestion @Impetus_Maximus. I tried, as well with the beta, no luck. Might be a problem of the flash cart :/ anyhow happy 2024 :)