the highest availability service i think is S3 at 4 nines

you might be thinking of durability for s3 which is 11 nines, and i've never heard of anyone losing an object yet

no, it's probably Route 53, touted as having "100% availability" (https://en.wikipedia.org/wiki/Amazon_Route_53)

hah, that's funny as the outage seems to be caused by DNS issues

Route53 was still resolving DNS entries just fine. But it looked like someone/something removed the entries for DynamoDB.