Realistically, my advice is. Document as little as possible. Build processes into your tools so it can be tested and repeated. Documentation that can get outdated, will be outdated and even worse be wrong. And, for example APIs can be organized in a way that documentation can be automated, so its never wrong or outdated, by choosing to use API contract first, like Protobuf or implementing via OpenAPI specifications. If you are implementing a specification of some kind, keep a copy of the specification version you have implemented checked in with the code.
Other things I have seen is f.ex. code that implements a business process, also can output itself as a Graphviz drawing, describing the parts of its own structure.