OT requires centralized server.
In my experience if you are persisting your edits or document state, you have something that creates an ordering anyways. That thing is commonly an OLTP database. OLTPs are optimized for this kind of write-heavy workload and there's a lot of existing work on how to optimize them further.
But now even S3 has PUT-IF, so you could use that to create an ordering. https://docs.aws.amazon.com/AmazonS3/latest/userguide/condit...