Why are you buying something that can't support multiple simultaneous buyers?

I only buy things where I won't be unhappy about the price I bought them even if crypto prices decline by 80%. Mostly things with market caps under $20M. The lack of liquidity doesn't bother me. Either the technologies will get real world use and the tokens will get listed on major exchanges, or else they'll go out of business, just like any other tech startup.

How can I find out more about these opportunities?

That's the best time to speculate.

Depending on the secrecy of an asset to retain its value and your ability to buy it sounds like a very fragile position to be in.

If the price goes up it should be because the technology has become part of the backbone of the Internet, not because people are promoting it on social media when there is zero volume.

So the market cap is you. This doesn’t apply to bitcoin.

Maybe. But if an institution were to accumulate $1bn of Bitcoin through exchanges, I'm pretty sure that would drive up the market cap a lot more than $1bn.

What's the difference between that and the same company buying a pennystock?

This is how markets work.