Hi, I saw that Steam got that update at long last after so long, so the GOG version should get it as well. Anyone knows when though? I only know it will be added "some time later".

Thanks for sharing, I haven't read anything about. I suggest you to contact the developers directly and ask them to upload the patch here.
I'm reporting the issue to this thread, that has been created specifically for this purpose.

I was about to buy the game – now I'm not sure anymore.

I contacted the devs and asked them to share the update here. They said they would contact GOG but nothing so far.

So far the new patch is not anywhere to see, at least not for my GOG copy. It's still stuck with the 2016 patch. Can anyone else confirm if the Beach DLC zone was added anyway, or is it still missing compared to Steam?

Yeah, hasn't been updated since 2016 on GOG.

It seems that there have been Galaxy-only updates for Windows/macOS on 2022-11-04.

That might be better than the situation for Loop Hero where there isn't even that. I'm not buying anything from Devolver until at least everything is updated.