I am not sure if I got you or no, and apologize if that’s not the answer to your question. So I have the ELGATO HD60S and every retro console I own work fine using the OSSC 1.6
I tried worked fine!
4. Sega Genesis
5. Dreamcast ( VGA )
I use scart cables from RetroGamingCables and they look amazing even with 2x ( My opinion )