I've got Node Red v2 running with multiple instances to handle simultaneous projects. I've got a reverse proxy (traefik) sitting in front of it to handle the url component so that it's same except for the uri. I did read that there were intentions to decouple the projects portion of Node Red so that all the projects could run at once but I've not seen any update to this. Has this been implemented or in development? While what I've done works, it would be great to only have to run a single instance of Node Red rather than a handful.
Not sure where you read that, but that isn't in the plan.
The core runtime is single tenant - it runs one set of flows. That isn't something that's going to change any time soon.