If you have the time. I have a few questions.
1. I can tell you are using HTTPRequest to make the calls to your server. Are you using specific headers such as no-cors to eliminate CORS issues? Do you have any sort of info you can share on what worked and what did not when it came to CORS issues specifically? I find some browsers very finicky.
2. Are you using a single threaded web export or multi threaded? Also do you use threads in your HTTPRequest? Why or why not?
3. May I ask which version of Godot you are using?
4. Do you plan to launch this game on steam?
Thank you again for your time. I have been playing with similar ideas and ran into way more CORS issues than I expected, however I got everything working after a few hours and specifically making sure that the cache was cleared.