Every year or so I check back in to see if Cognito has gotten any better. I hasn't. I'd love to use it, but some very basic things are just not done correctly. Yan Cui has a nice writeup on Cognito [0] that touches on some of its shortcomings.
My blood pressure is still coming back down from AWS having an all-day outage during a holiday week last year, because Kinesis had an issue and it turns out their entire infrastructure depends on that.
[0]: https://theburningmonk.com/2021/03/the-case-for-and-against-...