Feels like there are a few categories of services from cloud providers,
There’s the basic infrastructure we know and love like S3, EC2, etc.
There’s the higher level but still basic stuff that just makes a lot of sense. I like ECS + Fargate, Lambda, DynamoDB, SQS.
And then there are the tarpits. CloudFormation. Cognito. Step Functions. API Gateway. They do something useful (otherwise why would they exist?) but the main point of their existence seems to be to trap you in AWS, and the fact that they solve a problem seems secondary. Some of them are cheap (CloudFormation is free!) but in general they seem like expensive alternatives to simpler, cheaper solutions.
I caution against using DynamoDB when just starting out. It’s too easy to paint yourself into a corner.
The further up the stack you go, the worse it gets - but, honestly, Cognito and API Gateway are no worse than mid-tier.
The really nightmarish ones are the likes of CodeStar, AppRunner, Directory Service, CodeCatalyst, and 90% of anything under the Systems Manager heading. Things that tend to be glued together from multiple lower-level services with a sprinkling of vendor lock-in on top.