Utrecht, dashboards behind me. The lecture I give every founder who asks about ads:
Do one channel well for six months before adding a second. The founders who win at marketing are monogamous until it hurts. Every "we do SEO, content, affiliates, and a bit of Meta" is four failures in a trench coat.
Cohorts, not screenshots. Anyone can show a good week. Show me week-1 versus week-8 retention for three cohorts and I will tell you if the channel works.
Price before traffic. If the math does not work at 100 visitors, it will not work at 100,000. Fix the offer, then buy the crowd.
Ask me for the cohort, not the screenshot. It is on my wall. My wife hates the wall.