only unofficial builds to date, see this thread for more
https://community.e.foundation/t/xiaomi-redmi-note-9-merlin/23793
User itsclarence linked a local_manifest that is an easy starting point to build a current unofficial. Also an older 0.15 build is accessible.
The repos inside the local_manifest see regular attention from PixelExperience, so I’d say it seems in a healthy condition - if someone will do community builds every few months it would be good enough™ short of having a Lineage or /e/ maintainer.