Manual internet account settings not accessible in Mail app on Mac mini with macOS Sequoia 15.5

Mail on my Mac Mini does not always sync with my iPhone, especially not deleting emails in my Bigpond account. All Internet settings are correct on the iPhone (16 Pro) but I cannot check the settings in the Internet Connections of the Mail App. I cannot find a way to manually get into the Internet Account and there is no way I can find to turn off any 'automatic settings' that must be present. The pathway to these buttons do not appear to be present in Sequoia 15.5 OS.

If there is another way to check the Internet Settings I would love the hear. Ken

[Re-Titled by Moderator]

Original Title: OS Sequoia 15.5 does not allow access to manual control of an internet account, especially to check settings