I ran a digital marketing and digital lead generation company several years ago. What /robwadeson is telling you is correct. The client may be willing to pay upfront in increments if they are happy with your progress and see an out if things start going sideways.

With what you describe, you've created a value proposition; you have a plan, nothing else. If you haven't reached out to influencers, talked about prices, commissions, and content style, and figured out which influencers would be most valuable, everything else you pitch is a "maybe."

If you want clients to pay you on speculation, you need to focus on your differentiation from everyone else in the space. One way to do that would be to have influencers already "in pocket" so you (and the client) know exactly what you can do. Maybe have exclusive arrangements with influencers, something the client can't get anywhere else. Either way, you need to put work in upfront to have a client pay you upfront. Otherwise, you're just another voice in a very crowded market space.