similar experience on my 2022 Model Y Performancelate December 2021 build. Loading up the viewer allows me to see stored dash cams but not sentry events. If a sentry event appears, clicking on it results in a grey screen or messages saying media is on a different source (something like that). Issues started with the late December updates. Prior to the late December update, it was working great. Only had my car for a week or so before the dreaded update happened.
I have manually formatted usb using windows, Mac, Tesla car. I have tried using different USB stick sized 128gb (extended fat32) and 32gb (Fat32). Tesla computer said 32gb stick was too small and sentry mode wouldn’t activate.