im using the exact same setup and im also experiencing latency. its bad enough where it becomes difficult to play.
and like you said sample rate and buffer size have no effect on latency.
if you were able to find a workaround or solution, i'd love to know :))
Hey guys I am also using a Focusrite with a SM-5S and also had such bad input lag the game was unplayable. I switched to a USB lapel mic I had lying around and the game instantly became playable, I think unfortunately the Focusrite just adds too much input latency for a game like this sadly! One way to help resolve it would be for the dev to add a latency adjustment slider so you can push the samples of your recording back in time by a fixed quantity if you know you have input latency. Rhythm games often have an input latency adjustment tutorial for things like this.