Sure, Lambda is fine for that small app, but I once inherited a 100k/month mess of SQS, Step Functions, API Gateway, Cognito, Lambda, ECS, AppSync, S3 and Kinesis that made me want to go into carpentry.
It wasn't simple, it was't quick to make, it wasn't cheap, it wasn't fast, and no: it did not scale (because we reached the limit of Step Functions).
The default limits are _very_ conservative in large regions
(Admittedly, by the time you've asked for those limit increases you should probably reconsider what you're doing, you're bleeding $$$ at this point)
Feeling like you’re getting a special deal overrides objective thought. There’s a bunch of this stuff in AWS and it all feels dirty and wrong.
Serverless monolith ftw
I wrote a bit on how to achieve this with .NET (but probably applicable to many other frameworks/runtimes): https://chrlschn.dev/blog/2024/01/a-practical-guide-to-modul...
(It's inspired by the Google paper, but obviously a much simpler implementation appropriate for most non-Google scale teams)