If you are launching the hoyo launcher through heroic then that will also have to obey Flatpak permissions. Since that is how the containers work.
You could try enabling full filesystem access just to test whether is it Flatpak permissions blocking you.
Since it sounds like this is your home router since you mentioned you use Comcast. If you are testing the site from within your network using your external ip then you are possibly running into a loop back block. Comcast does not allow traffic that originates from within your network back into your network.
Try the ip/site from a Hotspot and that might work.