Ask HN: What are you missing in synthetic monitoring

I'm really curious how small(ish) startups are monitoring their most crucial business processes. Passive monitoring is mostly a pretty well solved problem: the amount of triggers and alerts I can set on a free Datadog account is amazing. However, for synthetic monitoring the market is vastly different and more expensive; Not so much simple pings but more specifically multi-step, selenium-based or otherwise, monitors. What are your experiences?