FWIW I have an M1 MacBook, and Resilio isn't too bad for me. I'm seeing CPU under 2% and it's not registering as high battery usage, so it may depend somewhat on your usage.
It should also be noted that Dropbox, which is a much much much larger company still does not have an Apple Silicon build yet, nor do they have any public comments about when one will be available. In fact, earlier builds of Dropbox failed entirely on Apple Silicon.
So, while I hope that there is an Apple Silicon native build coming, I'm willing to give them a little time.
Now, if we get to the end of Jan / Feb and still haven't heard anything, then making some noise seems more reasonable.