I'm sorry for these issues, I also don't know what's going on with that. My guess is it could be something to do with the engine? It handles all of the exporting on it's own, and I also had a similar issue with playing a different test game I made with this engine. It's a pretty niche engine so it's possible? I will look into other things as well.
Do you think it could be something to do with how I compress the .zip files? I just take the export folder and compress it with like the default windows function to compress the .zip file.
If you have any other potential explanations, let me know! I want to figure this out too!
(edit: something else to note is that an indicator to know if the menu is done loading is if the music starts. if it's started, the menu is done loading and should be clickable. just wanted to note in case it's relevant)