Don't the Hollowgram rings fit the Cannondale One crank and spindle? With many things in short supply for new bikes, I'd get on Cannondale's site and push that button that says "check local bike shops" and then call each one.
Otherwise what BB shell is on that frame? If you are willing to have the BB changed and get an entirely different crankset you'll have more options and might find something decent considering the current inventory scarcity.