I have a Clearaudio Innovation with two tonearms so a dustcover is out of the question anyway. It would be expensive to have one made, and impractical and cumbersome to use when the TT isn’t in use. I just don’t bother covering it with anything. I have a cosmetic brush I use to wipe off the platter before playing sessions, and a feather duster to occasionally dust the plinth and arms.
When I had Rega and Linn LP12 turntables, I removed the dustcovers entirely for playing records.
My environment is somewhat dusty but not terribly so. My wife vacuums the listening room on a regular basis (at least once a week).