Been playing my Saturn games on my Series X all weekend! A few seem a bit wonky (got some weird ghosting/slowdown on Last Bronx, for example) but Sega Rally is perfect and I played some solid Manx TT last night. Can even easily switch between the Analog controller and normally digital controls with a button press (for those games that support the 3D pad like Nights and Sega Rally Championship Plus).
It's giving my Saturn library a second life honestly.
Had a small dabble with Dreamcast (got Virtua Fighter 3tb working last night) but gonna try Sega Rally 2 and MvC2 tonight.