FWIW, the soft limit for 70 units is about using the global module, which provides consistent state in the cluster (i.e. when you do a change, it tries to change all nodes at once).

The default Erlang Distribution was shown to scale up to ~300 nodes. After that, using sub-clusters is the way to go and relatively easy to setup: it is a matter of setting the "-connect_all false" flag and calling Node.connect/2 based on the data being fed by a service discovery tool (etcd, k8s, aws config, etc).

PS: this data came from a paper. I am struggling to find it right now but I will edit this once/if I do.