Can somebody explain to me why I wouldn't just rent a 40 EUR dedicated server from Hetzner with unlimited traffic and gigabit uplink? His 600GB/day is way less than what you get over a gigabit link within a day. Sure, sudden bursts would perhaps "throttle" at a gigabit, but according to his article that was only the cloudflare proxy anyhow, so no pain in having that take a few seconds longer. As far as I am concerned…
I'm fan of cheap VPSes too, but I'd like to have things like metrics out of the box
Getting metrics on that is not a hard problem, there are various projects that are relatively simple to set up.
If you want to make it easier manage resources, metrics out of the box, and avoid (hoster) lock-in then I'd use a hyper visor distro like Proxmox VE (disclaimer, am a dev there) or the like, and you can migrate (or backup/restore) VMs or Containers easily to other providers. That gives you a (relatively) simple web-interface to manage most things and also opens the possibility to just add a second or third dedicated host down the line to scale out, if those new hosts are in the same DC or have a good interconnect (latency wise) you could even cluster the nodes.