The problem was processes section in fly.toml. This was something that came automatically with using flyctl launch, but it’s seems to be mentioned nowhere in the docs.
[processes]
main_process = "node server.js"
Removed this, and now autoscaling has an effect, and true to documentation.
But, still, all 4 instances (min) are at 1 region. Would these be distributed automatically, or should I do something? I would like them to be at seprate regions.