Well, cutting ride's capacity could be counter balanced by adding more trains, ensuring rides work at their maximum capacity even if the day is slow.
However, this poses another problem: with so many guests per hour grabbing onto bars, harnesses, how can you make sure that rides are as sanitised as you would expect? If you really want to do things right, I guess you could have a crew disinfecting every train upon arriving to the ride's station, which could as well hinder operations. Or you could just make it compulsory for everyone to wear a mask AND gloves prior to entering the ride's queue area and boarding the train.