I have disabled Akismet and most of the other plugins with no joy… I don’t see this issue with Brave browser …. but other browsers are giving the same issue..
You can try disabling all plugins aside from GP Premium. If the issue persists then the problem may be at the server level.
What server are you running?
Aside of the ads on the site – the only other thing i can see is a Google Tag Script for Active view being loaded, and its not until the associated scripts are loaded that the sidebar appears.