[mariusor]

The new movement to put forward federated small size communities for link aggregation and discussions has maybe a solution for your problem. The project I'm working on currently has these exact things as goals: https://github.com/mariusor/go-littr#about

Basically it wants to be a service that is easy to deploy, not resource hungry and with minimal overhead over the base federated protocol (ActivityPub in this case) that allows it to sustain a small/medium community that shares similar interests, but also have access to the wider federated community (composed of various instances of Mastodon, Pleroma, Pixelfed, etc.).