I struggled for a while trying to get GitHub hub to display some html. It can be done, but not as slickly as other GitHub functions.
I had a page at https://github.com/colinpaicemq/zpymqi/blob/main/docs/test.html, but whenever I displayed it, the raw html was displayed. My challenge was to display the html as rendered html.
Display your repository in a web browser, and select the “settings” icon. On the settings page, click on “pages” in the left hand window. When it displays “GitHub Pages”, go down to source and select on the “None” pull down.

Select “main” to make pages available, or none to make them unavailable.
Click “save”.
It will then display
Your site is ready to be published at https://colinpaicemq.github.io/zpymqi/
After a several minute delay I could display my page at
There is always a few minute delay before displaying the pages.
Compare this site with my source site