Hi Jleclerc07,
You’ve done some great troubleshooting so far. The following steps could lead to a resolution:
• "Install all available Apple software updates, which can include updates for Safari. If you installed any Safari extensions, update them as well.
• Temporarily turn off Safari extensions to be sure they aren't affecting Safari in unexpected ways. Choose Safari > Preferences, then click Extensions. To turn off an extension, deselect its checkbox.
• Certain network settings, such as those related to using a proxy server or custom DNS server, can affect access to content on the internet. Even if you haven't changed your network settings, you might have installed software that changed those settings for you.
To find out whether the issue is with the network settings on your Mac, try viewing the website from some other device connected to the same network."
You can read more here:
If Safari on Mac doesn't open a webpage or isn’t working as expected
Take care.