Topaz Plugin no longer works after latest LrC update. LrC freezes, Mac freezes, has to force quit.

Which exact Lightroom Classic version is running on your Mac?

There was a major problem with some types of plug-ins in the recent 14.4 update. Lightroom Classic would not quit, and had to be force-quit. (The rest of the Mac continued to run properly.) However, this problem was fixed in the current 14.5 update, and the developer of a plug-in I use also fixed it on their end, so it got fixed on both sides.

If you are already on 14.5 and you are still having problems, then it might be a different problem than the one above. Plug-ins in general seem to work perfectly well on 14.5 on Macs, so if you are having trouble with one plug-in then the fix might have to come from that plug-in’s developer. Contact their tech support.