Since Golden Gate my Usenet newsreader/binary downloader no longer works - any suggestions for one that does?

Panic Unison usenet newsreader is unsupported (since 2014), and has been flaky for a while.

You’ll want to find an alternative newsreader anyway, given Unison is unsupported, has issues, and is not a universal app built for Apple silicon particularly meaning Unison won’t work at all on macOS 28.

You might find Apple or some third-party manages to get or keep Unison working for macOS 27, but I’d not be at all hopeful for use on macOS 28.

Mozilla SeaMonkey includes a Usenet newsreader. There are other options for NNTP clients.

This is why I highly recommend people wait to upgrade to a new major OS version. People should wait to ensure all of their third party software is fully compatible with the new major OS. It also gives Apple time to fix release day bugs. Plus it gives the user time to read reviews of the new OS to learn about new features and any common issues people are having with it.

I recommend people wait at least three months before upgrading to a new major OS version since most people have no immediate need to use a brand new major OS. Apple is in too much of a hurry to release a new major OS on a specific date, so Apple allows a lot release day bugs to exist on the launch of the new OS instead of waiting until the OS is actually ready for public consumption. Plus many third party developers don't have not yet released updated versions of their software which are compatible with a new major version of macOS.

Installing a new major OS on launch day (or within a couple of months) is considered living on the edge, so users should expect to have things misbehave. You should check with the developer of your third party app to see if they are planning an update to make their app compatible with Golden Gate and what their expected time frame may be for the release.