Ok I may have found the issue and temporary solution after some extensive testing and by process of elimination.
Since I could see the WebGUI was loading just fine on Incognito, I also tried other browsers and profiles that don't have my regular set of browser extensions. They all loaded fine and worked properly.
I then started to remove every extension I had one by one until I found the culprit.
It's a very niche issue, and doubt many people use this particular extension but it's called "Pocket Universe," and its a Web3 security-focused extension that blocks phishing sites, malware, etc. After disabling the extension the WebGui loads perfectly.
Anyway I have reached out to the support and devs of that particular extension to let them know of the issue and hopefully they can properly whitelist the Unraid WebGui and and improve that extension because its probably unknowingly blocking other legit sites too.
blitzio's post in Missing details and sections on WebGUI affecting browsers (but not Incognito) was marked as the answer