Forgot to mention, this is a MacBookPro running Catalina, although I did try on a different MacBookPro running High Sierra.
I see, well I'm not a Mac user myself so I'm not very knowledgeable when it comes to MacOS specific stuff.
I would still suggest trying to start from scratch as much as possible, deleting the earlier versions and re-installing the full version.
The first thing I would do, unless you have already done so, is to simply restart the computer and see if that makes a difference.
(One more thing, you could try to go into the save game data of Freerider and see if perhaps something went wrong there. If the data somehow got messed up you might be able to get it working by deleting the old save data. The data is stored at: ~/Library/Preferences/Freerider (or something similar to that) )