Just wanted to update this thread to let everyone know that we have reproduced issues with moving between images in the Preview window and are doing what we can to resolve them. My own testing, shows some quite different performance when using different color profiles, with sRGB (as as Apple calls it on my MacBook Pro: "Internet & web") performing significantly better than the default profile for my MacBook Pro's built-in disaplay: Apple XDR Display (P3-1600 nits). Some other users confirm that changing their display profile improved performance as well. I understand that this is not a viable workaround for many folks, but it may explain why this is is not an issue for every user.
That said, I'll update the forum threads when we know more, but if you are experiencing an issue other than the speed of moving between images in the Preview window, please send an email to support@camerabits.com, as we have not been able to reproduce those.