Personally I would avoid rasperries like the plague here - they have many downsides when booting up rarely. I’d rather use a Mini PC or ZimaBoard, maybe a build on a MC12 leo (if you can still get it cheap),chuck it all in a cheap case and be good. Unless you have something with IPMI on it I would also invest in a semi professional KVM like PiKVM,JetKVM,NankKVM - and if you can’t stop/start power with that due to the device not following the standards maybe an IP switchable plug.