RetroArch

I can seamlessly transition between PC (Arch Linux) and my Steam Deck (SteamOS) without losing any in-game progress.

And the fact that it even has a Linux native version and everything doesn't come preinstalled but you can choose which console core download through steam DLCs makes it so much betterr; I swear I love these kind of community-made tools :D

RetroArch offers a comprehensive suite of emulators within a single program, complete with cloud save functionality and multiplayer capabilities.

Save states allow instant suspension and restoration of gameplay, while rewind functionality provides the ability to step backward through recent actions—an invaluable tool for difficult retro titles.

So many possibilities, often better performance, tons of video filters, interface themes, hotkeys making life easier, QoL content, almost unpercievable input lag (if set up properly).