Hi Will,
Thanks for your message. I am not sure this is related otherwise you would get the same message.
The bin/ancestris file should be there obviously because it is in the downloaded package.
Ideally you should have java 17 active (what does java -version gives you in a terminal window?) and run Ancestris 12 because more recent.
If I were you, I would remove all ancestris versions (delete folders or apps), remove java 8 (not sure how), make sure java 17 is still active (open a terminal and type "java -version"), then reinstall Ancestris 12 and try again.
Let us know,
Frederic