Hello @buzzykiwi. If you have already gone through the steps detailed in the link and it still does not work, let our Support team help. You may connect with them through https://gopro.com/help/ContactUs . When you do, please make sure that you have access to your computer, the Internet and your Fusion camera.
Just to verify, have you already downloaded Fusion Studio v1.4 and installed the Fusion plug-ins for Adobe Premiere 2019 using the download links in this article? After you installed Fusion Studio (any version), remember to install the Adobe plug-ins to install the versions that support the 2019 versions of Premiere.
If you've already gone through those steps to no avail, please let our Support team know so they can look further into details and assist you on the next steps. You may reach them by phone or chat through https://gopro.com/help/ContactUs.
I FOUND THE ANSWER :)
For anyone else who was searching for hours with no luck.
I updated Adobe Premeiere pro 2019 to the newest version and now the GoPro plugins show up.
I did already have Premiere Pro 2019 but there must be a newer update of the same year that I had not downloaded.
Hope it helps others out there