Painter 2019 will not open, & package files are nowhere to be seen


I have the exact same error message / report and the exact same issue as stated here. I'm currently running Catalina on a 2017 Macbook Air, and bought Painter 2019 through Humble Bundle. I've tried repeatedly to uninstall and reinstall since the initial purchase, but with no luck.

When I found the above link and realised it described the exact issue I was having, I tried to follow the solution, but it's impossible as there is no Downloads folder inside my Corel folder.

I go to Drive / Library / Preferences / Corel

and the only thing present is a folder named 'Messages'.

Any help would be appreciated as I've yet to be able to use this product I purchased weeks ago.