The easiest way to accomplish what you want is using goals within automations. Goals are definitely a bit more tricky, but are worth digging into more.
Did you see this conversation during your searches: How do I cap the number of automation emails a contact is sent each day/week?
If not, go ahead and check it out. If you already saw that conversation though, let me know and I will suggest a few other alternatives.
Cheers,
Perry