Don't have an answer myself, just bumping the initial question to
indicate that the OP is not the only one interested in not having to use
an Oculus specific kludge to run portable code.
The Unity related documentation should state what release the
instructions were written and tested using so the reader can have some
indication of how stale the content is likely to be (using the current
Unity 2020.3 LTS I don't recall the last page ...
