When it reaches the “good/mostly done but not perfect/could still be better” stage, it’s time to pre-release it for alpha/beta testing while you work out the kinks and add features.

I remember playing Minecraft in alpha version before it even switched to beta. It was fine.

Even full releases can have updates and expansions to add new features, it’s totally fine. But the core development of the game shouldn’t be rushed just to get it published.