- You can subscribe to any community or add the instance to the Allowed Instances
- Yes you can search the communities through your search e.g. !fediverse@lemmy.world an subscribe to it
- My Instance is running on Hetzner I am using the CX21 (2 Cores, 4GB RAM, 40GB Disk Space) and its running really good (Its just me on this instance for now)
- definitely yes 😁
As far as I know, there is no current arm Docker image for your Raspi 4. You could rent a cloud server. E.g. Hetzner. I use the CX21. It runs very efficiently for me.