Ehh.. you seem to have thought of this deeply enough, and I'm pretty sure you already understand the risks anyway. While I'm personally not a fan of using my bitcoin as collateral for anything, you do you. In the first place, only you yourself understand your knowledge, expertise, and how good/bad you are in general with real estate so we really can't encourage/discourage you.

Personally, I prefer starting(and growing) small, low-initial-capital businesses. But then again, that's just me, and the "best" ways of earning wealth is going to differ from person to person.