I'd have to say Moderna, which is 11 years old and also publicly traded, but should qualify because of how recently they actually brought their first product to market.

Considering every non-cash asset is wildly over-valued right now, I don't know that I believe any non-health startup (that I've heard of) is undervalued.

I have a lot of faith in Rivian, for example, but they're valued ar $80B before even selling a single vehicle. Look at what happened to Workhorse if you think that's reasonable.

Moderna's market cap is only $170B, which seems low considering their potential to make hundreds of billions annually if they find even one new application of mRNA technology (e.g. cancer treatment).