If you still follow this forum, You can check StreamingEnabled. StreamingEnabled can improve gameplay of players with poor network and loading parts.
+Make sure to choose the good level of graphics quality in Settings (in-game). Your Roblox depend a lot of your Graphic card. (if not WIFI). GT 970M Kepler is not equals to a GTX 1080ti from Nvidia.
If Iām Not Mistaken But This Is Due To You Using That Third Party Application To Run Studio And Roblox On Mac Since Its Not Naively Supported, I Would Contact The Owner Of The Application To See if He Knows Why Its Happening