> I believe there is a single person that was in Redis and works there now, at least AFAIK. And this person stopped working at Redis long time ago (and was not a core developer).

It is probably more correct to say a bunch of Redis contributors left the Redis GitHub project and moved over to Valkey.

You can see there are a bunch of contributors listed on this page who seem to predate the fork and who have continued to contribute:

https://github.com/valkey-io/valkey/graphs/contributors

Particularly these contributors standout:

https://github.com/enjoy-binbin

https://github.com/madolson

https://github.com/soloestoy

https://github.com/hwware

https://github.com/zuiderkwast

https://github.com/hpatro

https://github.com/pizhenwei