I’ve made some tests, and unfortunately Disqus doesn’t like to be in an iframe which doesn’t have allow-same-origin.
I saw that it was modified for security reason, but I don’t know if we could add it back in specific cases, maybe tag the component as unsafe and warn the user about it.
However, Disqus does load correctly with st.html as it has allow-same-origin, but I cannot change the height dynamically from there.
One solution would be to have a height="auto" parameter, but even that is not that simple as there’s no easy way to support auto resizing iframes. The way I implement it is inspired from those two links (from the same author):