Nik 3.3 (25th Anniversary) installed on my MacBook running Big Sur, and works great from PhotoLab 4 and Affinity Photo, except for Viveza. It’s OK until you save your edit, then Affinity Photo crashes. This has only happened with Viveza, everything else I’ve tried has worked great.
Seeing the same thing here on my iMac.
I have the same problem with Viveza (Nik 3.3)