For 2019, we used OnShape with Windows laptops. We found it helpful to use simplified models where possible. For instance, in the MKCAD library, there are two versions of the PDP, one with all the details such as the holes for all the wires and a simplified one that is a “brick” with “PDP” on the top and just the mounting holes. One time, I tried loading the model for the whole field and it took forever. Afterward, I imported only the game elements that we were planning to use. I also simplified them, i.e. removed the support structure and fasteners from the platforms. I also simplified the model of the KOP chassis by doing things like deleting all the fasteners that were not on the outside surfaces, deleted the internal parts of the gearboxes, replaced the wheels with simple disks and deleted the pulleys and belts from the drive train. I recall having a student load the original KOP chassis model then the simplified one and the loading time was roughly cut in half. These practices would speed up the loading and model manipulation no matter what CAD package one is using.
We found a major bottleneck was the slow WiFi at the school, especially when more than one student was trying to use OnShape at the same time. Even loading datasheets from AndyMark was slow. The response was much faster and became acceptable when I set up a hotspot using my cell phone. It may have been a bit faster when using the wired network with fiber optic feed at home or the network at my workplace.