Tactical RMM

The Cool Thing that started the dive into networking shenanigins
https://rmm.upgrayeddsgarage.com

Proxmox VM Debian
4 generic CPU cores
8gb ram
50gb disk

RMM is Remote Monitoring and Management, basically you can make computers do stuff form home, useful for avoiding house calls for family. :P
Includes:
Screen sharing/Remote Control, for live troubleshooting and white-glove treatment
Scripting/CLI Access, for running health checks and powershell things
Patching/Scheduling, for updates and planned reboots
Alerting, emails/webhooks for "Hey is your server supposed to be off rn?"
Reporting (pro feature) Gather stats and make make PDFs and emails about it

This is the bread and butter for any IT department, and this one is free and open source. (Hosted instances and Support are how you make money these days)
The requirements are dead simple: a domain name, a cloudflare account (or similar DNS provider) and port 443 touchable.

Having broken and rebuilt it a few times, there's not much that goes wrong with it:
 You either let the cert expire and you just have to go fix that (agents normally fix themselves afterward)
 or you screwed up the dns again and nothing can hit the server (dumbass)

Haven't got enough stuff in it to stress anything, But it runs a database, and depending how many checks you run, how often, it CAN get noisy.