[temac]

The web has nothing magic.

People have been maintaining SW developed by 3rd parties for several decades. Something like 5 or 6, probably. With all the various amount of available documentation you can imagine, and that includes no documentation and really stupid code bases, or even no source code and you have to patch a binary.

So while I recognize it can be obviously cool to e.g. have virtually no code but simply use a well-designed and currently actively-maintained third party project, it is not always possible, and if it's not then implementing (or even just configuring) anything on top of fashionable software can also be done in crappy undocumented ways.

So the key is to actually have detailed and useful documentation, regardless of 3rd party stacks (or they very relative "absence", I mean probably don't develop your own web-server nor your own database nor your own programming language nor your own operating system nor your own web-browser...)