Influencer campaigns feel like throwing money into the void, how do you guys handle tracking & fairness?

I run a small Shopify brand and have done a handful of influencer campaigns this year.

The problem: half the time, I can’t tell if the influencer actually moved the needle. I get screenshots, “estimated reach” and some Shopify traffic spikes, but no way to prove conversions came from them.

I’ve tried affiliate links, barely anyone clicks them. Tried discount codes, customers forget to use them.

I want to do more influencer collabs, but paying flat fees with zero accountability feels dumb.

Curious how other brand owners handle this. Do you just trust the influencer? Pay flat? Go commission only?

Any system, tool, or structure that’s actually working for you?

(Serious replies appreciated, I’d love to make this whole influencer/brand dynamic less painful for both sides.)