Hey, I'm reaching out again to see if you'd still be willing to help me out fixing the viewport issue! No worries if not, but if you wouldn't mind, could you:
Download the Windows .zip and see if the viewport works as a downloadable.
Access the following link and see if the viewport works there:
https://eastshrine.itch.io/foolsgoldviewportfix?secret=JDGMkiwL8uEdCVDKGrEoNd6qc
Based on what you see there, hopefully I should be able to figure out what the issue is. Thank you so much!