Ship when the product delivers on one clear sentence. Everything else is v2.
The trap with data-heavy projects is that the feature list feels infinite — there is always another visualization, another model, another integration. But users rarely care about 80% of what we build pre-launch. They care about the one thing that solves their immediate problem.
I'd say ship when one clear workflow works end-to-end without breaking. Polish is what the first 10 users teach you to prioritize.