The xdg-open command gives an error and displays an HTML text box instead of opening a browser and displaying contents of the URL. Worked on Fedora 38 with no issues.
Tried with well known URLs example google.com and get the following errors:
MESA: error: ZINK: failed to choose pdev
libEGL warning: egl: failed to create dri2 screen
OpenGL Info
I ran xdg-open http://www.google.com & and it worked fine no problem F40 (GNOME Classic on Wayland) and Firefox. I have Intel UHD 630.
If the browser works normally without xdg-open, I don’t think graphics would be an issue, but it looks like something isn’t set-up ideally with your graphics stack (llvmpipe, zink, and DRI2 mentions).
Also I prefer gio open instead of xdg-open 
but I’m sure that doesn’t matter for the issue.
xdg-mime default org.mozilla.firefox.desktop \
text/html x-scheme-handler/http x-scheme-handler/https
Thanks for your response. Where do I add this command or configuration:
xdg-mime default org.mozilla.firefox.desktop \
text/html x-scheme-handler/http x-scheme-handler/https
Copy-paste the code to the terminal as is and then hit Enter.