My device that I use it on is a raspberry pi with 4 gb ram. Would virtual memory make it safely support more than 8 players? And it also has an ARM processor, which is not very powerful. Would that get in the way?
Virtual memory probably isn't a good option for performance but you don't necessarily even need that to handle 10-20 players. You could try
- allocate 3 gb of your ram for the server (java -Xmx3G -jar ...)
- lower view-distance in server.properties to 6-8 to reduce memory usage
- lower network compression-level in nukkit.yml to to 3-4 to reduce cpu load