Given how much capitalization AWS and Azure account for it's surprising how little progress has being made in many areas.
A true serverless RDBMS database priced sanely that basically charged for qry execution time and storage without need to provision some "black box" capacity units and would be suitable for a large scale app. Most of all workflows that require contacting support and arbitrary account limits that force you to split solutions across multiple accounts wtf.
Both Dynamo DB and Cosmos DB offer effectively what you're asking for.
Limits are a risk that must be mitigated but they aren't arbitrary, they exist to avoid interference of one customer on to others. They protect the service which, to providers and reasonably so, is more important than any one customer.
DynamoDB is really crappy key value store with poor feature set and really bad limits.I am talking about real SQL RDBMS like Aurora Serverless but not built on top of legacy codebase and shoehorned into the use case. As far as account limits if I consume X+X things across 2 accounts vs 1 account what did it protect exactly? An org can have any number of accounts and add them at any time.
