For my day job, over the last 2 years we have discovered and reported multiple issues with Keyspaces, Amazon Aurora, and App Runner. In all cases these issues have resulted in performance degradation, and AWS support wasting our time sending us chasing our tails. After many weeks of escalation, we eventually ended up with project leads who confirmed the issues (some of which they were already aware of, yet the support teams had wasted our time anyway!) and (some of them) have since been resolved.
We are stuck with Keyspaces for the time being, but now refuse to use any non core services (EC2, EBS, S3). As soon as you venture away from those there be dragons.