This isn't really a drop-in replacement; they don't offer transforms out of the box.

Admittedly some of the transforms proposed in this article are a little simple & don't represent the full space of feature eng requirements for all large orgs

Actually feast does support transformations depending upon the source. It supports transferring data on demand and via streaming. It does not support batch transformation only because technically it should just be an upload but we can revisit that decision.

I think feast is sunsetted

There are new maintainers: https://feast.dev/blog/the-future-of-feast/