I've worked with some large Jira installations and I don't remember ever running into 10s page loads without a broken VPN/internet connection. This sounds like a very very broken setup.
My company uses Confluence (NOT self hosted) and it regularly takes 10s or more to load a page on a 400Mbit connection. Text content only, no diagrams. Confluence is a joke
Ours doesn't take that long usually, but it sure can be slow.
Their assistant might not be but what does the exec know?