Thank you all for your help. It's frustating that the developers won't create a solution for this, considering there are likely many macOS users. I realize that this game is catered towards Windwos users, but we're paying customers too, so the lack of any attempt at support is interesting.
Anyway, I just got Parallels to run the 64-bit update, but now I'm finding that the rooms are flashing around me, with random objects of the room disappearing and then reappearing quickly. It's disorienting because I can never get a sense of what a room is like due to the room changing so much around me. I thought this was a lag that was related to the number of people in a room, but it happens when I'm alone in my World too. One thing I've noticed is that the flickering doesn't happen in the original room - is this related to Worlds that users create vs. the developers?
I then tried creating a Windows partition using Bootcamp to run this program, but then ran into the issue of not being able to change my camera view with a right-click. All of these difficulties are despite updating to the new 393 patch.
Is there a graphics setting I should toggle/change to fix these issues? I have all the reflection/light/shadow settings turned off, and the Graphics setting is on "Low."