>>1407017No, the moving parts will always make a slight sound, more noticeably so in low-middle tier groupsets like Tiagra.
And no, there's no such thing as "gears that are not meant to be used" beyond big-big or small-small (crosschaining) which also stopped being an issue years ago on 2x drivetrains, it may accelerate chain and cog wear a bit but it's not like it's gonna fail catastrophically