I'm very much onboard with much of the other advice, and would have agreed with this bit for something like 25 or 26 years of my life. My goodness, I sure wasted a lot of people's time.

Create more value than you capture, but don't be afraid to sell. It gets easier with practice, and it is a core competence in a startup founder. You've got to be able to sell to customers, sell to investors, sell to the press, sell to your employees, etc etc. The most direct path to what you want is a) describing why it is in X's interest to give it to you and then b) asking for it. It works. Astoundingly well.

Relatedly, "quality content will win out" is not a marketing strategy. Much closer to the truth is this old chestnut: if your ideas are any good, you'll have to shove them down people's throats.

P.S. You're not a nobody. You're someone who has something X should want, but does not yet have a personal introduction, means of social proof, or whatever it is that the supposed "somebodies" have. You can fix that, and you should fix it, ASAP. The ROI on fixing it will be spectacularly better than more cold emails.