Is there a typo in your post (maybe when replacing the real user names with generic ones)? You mention you’ve made user user the owner of pgdata, but ls -l displays myuser as the owner.
FWIW, you want to grant another user access to a specific folder within your home folder, but unless you’ve granted the user user rights to traverse your home directory (execute permission), they cannot access it. It would be better to put the pgdata folder somewhere user can reach it, then grant the necessary permissions.