When we moved a very high traffic client onto Kubernetes, we tried to split up their stack a bit.
The site is largely static, except for comments. So there was definitely an opportunity to save resources if we could spin off comments into a microservice decoupled from our main Drupal application.
We decided to use Coral Talk, and I spent quite a bit of time working on various custom plugins to fit our use-case.
Many of those remain private repos because they were very specific use cases, but the CKEditor plugin is public.
It was built with a mongodb backend and a React frontend that used GraphQL. It was deployed on a site that regularly has around 5-8k active users at any moment, and hummed along quite nicely.
I made some issues and one accepted PR in the process.