There’s always those Mayflash converters for an original Saturn pad. I can’t seem to find any conclusive evidence of input lag or lack thereof so YMMV.
There’s also been more boutique converters but none seem to be currently in production.
Yeah, input lag isn’t really all that bad from my experience. It’s more that the converter is awkward and I have a pretty small living space so I find they fall off my desks and tables from time-to-time. One of the things I really like about the original Saturn pads is how much weightier they are than the USB ones. Not really directly about quality there, the added weight just feels good to hold in my hands.
The Hori pad is pretty great! For some reason the digital pad (DP on the controller) is really jittery though? Even when I gave the game Up Left, Up Right, Down Left, Down Right inputs, for whatever reason it oftentimes seemed to stop reading the input, making movement pretty awkward (my character was constantly stopping and starting while walking). Switching it to the Left Stick function fixed it though (had to do inputs again).
The Buffalo USB gamepad (an SNES gamepad) is cheap and works pretty well too if you’re just playing old emulated games. Obviously am unsure how long it will last though, just got it.