We’ve experimented with this at Ambar. 4000 CAC can be good or bad depending on the LTV of your customers. But if you can indeed get something reproducible you can work on optimizing if you’re within the order of magnitude of being profitable.
But on a small budget, before dumping money on PPC, I recommend getting better signals on intent, even if you don’t get a conversion.
Measure what people are doing once they land, and optimize for better engagement. since ready test your theory to see if you can indeed get customers for 4000 bucks or less.