Launching beta version (70% complete) vs waiting and launch a complete product?

Hi! There are 3 killer features I want to showcase about my product and I think they need to go together in order to make an impact. Two are ready but the third one is not (we had built already but we need to migrate to a different tech stack and it's costing us time).

I don't feel 100% confident about launching the product with only 2 features (without payment of course), but at the same time I want to see users response asap. Sometimes I wonder whether we should finish the product at the cost of delaying the project launch, but at the same time I don't want to delay anymore.

I am in such a big dilemma.

1. Has anyone gone through the same experience? What did you decide to do?
2. If you launched the beta version first, how was your experience? Do you recommend to launch the imcomplete version and see the market response? How long after should we launch the updated version in order to keep momentum?

Thanks in advance!