About the switch. What switch do you have? Can you give us a name? With some switches you have to turn on the ports before you can use them.
For the server: Depends on the server. I started with Ubuntu-Server or Debian to play around with docker containers. If you want to play around with different OSes try Proxmox to create VMs
Looks like some very capable machines.
Uptime Kuma and Grafana. Uptime Kuna to monitor if a service is up and running and Grafana to monitor the host like CPU, RAM, SSD usage etc.
Have the same setup for VSCode. I use it to edit files and start/stop Docker containers. Of course it can do much more. Very convenient. Maybe even more convenient than Portainer.
Sometimes it just little improvements but I enjoy them. A local Nextcloud is much faster than my cloud backup and cheaper. Adblocking makes webbrowsing much more comfortable. Home Assistant helps me to get up easier in the morning when it turns on the lights automatically. So yeah some things are very convenient.
Pihole or DNS-Blocker at all. My girlfriend tells everyone that she can watch content on the internet without ads. I guess I can’t get a bigger approval rating than that.