I am having the same issue. Since it just came out, don't see any fixes as of yet.

At least one other recent release seems to have the same symptoms: https://www.gog.com/forum/shenmue_iii/achievements

Do Achievements work with Galaxy 1.2 (which is what I use)?

And/or has the issue in the OP been fixed by now?

I was about to buy to this game, but if Achievements don't work, then that's a dealbreaker for me. So I need know whether or not they do.

And the guy in the Shenmue thread who said: "Achievements work, but they are all hidden on Gog" --- the intended meaning of that statement is extremely unclear. I have no idea what he is trying to say by those words.

I believe that achievements work normally, but they have the known invisible achievement bug, that is, only unlocked achievements are visible and not the complete list. This is because developers use this mode when they work on achievements, and they should change it with the release of the game, but often many people forget about it.

Those who have the game should send a ticket to support and they should be able to fix the bug very quickly.

The same thing should be done for Shenmue III.