Maybe you should join forces with YuNoHost. It let peoples selfhost on a Raspberry Pi or any old computer. Can be a "when I start it spare board only visible at home".
They already have a lot of apps packages that are 1 click to install. Maybe you can discuss to propose an option in their package script to reduce network to the current machine?
The only downside to this approach is that their solution is targeted at being an entire OS. So I suspect most of the work would be to extract the app management from the rest?
One issue I have with your idea is that most open source servers/app are designed to be run on Linux right? Not every users use it on their main machine. You also talk a lot about docker… does it work on Windows? I mean WSL sounds like a nightmare to manage with script, for other peoples. From my point of view, YuNoHost solution is easy enough for a layman, and they will be happy not to break their main PC, have access from their phone, … even if only at home.
SpaceX is a strange player in this field since they test their hardware to the limit. Here is an old video with thz falcon explosions https://www.youtube.com/watch?v=p9FzWPObsWA. It is 8 years old so does not contaign the starship tests.
On the other hand of the spectrum, you have all the national agencies that simulate a lot and test in controled environment. Did you see SaturnV explosions during development ? Or Artemis launch ? Ariane 5 only had 1 bug, Ariane 6 have a flowless start.
Just not the same test/development phylosohy.