I'd really recommend docker/podman etc. if you are going to host more, especially with portainer. makes things a lot easier to manage when you have lots of services hosted.
then again I'm not sure you could get much more running on an RPi 2. how does it hold up in general with the stuff you have so far?
I have Kanboard up in a Docker container.
Not the most flashy or modern but lightweight and gets the job done. Good if you want something very easy to spin up in Docker.