First of all: I love the idea, effort and everything in general. So take my comment lightly.
Datadog is big because they shipped a gazillion integrations across I don't know how many products.
Anytime I see a "alternative to Datadog" I think: so you are going to have an agent and integrations page that integrates with everything from HAproxy to Kafka to the full AWS and Azure API's and etc. etc. etc?