You can use actual CH Cloud on AWS?..

I'm aware; unfortunately that then leads to "must have a vendor approval" and a lot more process. If it were RDS, then it'd just be provision and done.

AWS acquired DuckLabs recently, there is a chance they will release a product competing with CH/Snowflake as a new RDS offering

Doesn't aws marketplace help with that?

No, because the issue is navigating legal agreements with your vendors, not the ease of deploying. With AWS Marketplace you are making a new legal agreement with the vendor of the product, not with Amazon.