TestFlight on Mac OS

Is there any link to test DeltaChat on MacOS Monterey via TestFlight ?

not yet, test versions are still announced on this forum, we plan to do the next one by the end of this week.
Also I won’t promise that we do TestFlight releases for macOS, because it’s additional work that not that many people would profit from currently.
Similarly like we don’t use the beta program of the playstore actively currently because it’s more work than just linking to the apk’s that we have already build.