After testing by disabling all plugins and re-enabling one by one, I have found out that the ExtendedActivity plugin interferes with Gutenbergs embed YouTube video function and (without any error visible) does not show any video on the site.
This is still an issue for me. Given that this was a paid extension I would appreciate if I could get a resolution to this problem. It is after all completely invalidating the plugin since it’s supposed to allow for additional features in posts such as video which doesn’t show.