If you want to self-host Neo4j in cloud environments, that's doable today in a variety of different ways:

https://neo4j.com/developer/guide-cloud-deployment/

As others pointed out in other threads, this can be done for free for startups of a certain size (https://neo4j.com/startup-program/), and eval licenses are available (https://neo4j.com/lp/enterprise-cloud/?utm_content=aws-marke...)