isn't that the "works on my machine" of this discussion? What's the Apache Tika for .net then? I don't mean, pdf parsing, I don't mean .docx parsing, I mean a framework for interacting with all their supported types <https://tika.apache.org/2.9.1/formats.html> with one surface area?
You're right, how silly of me, I'll install some rando's 6 year old build of it right away. But in seriousness, that readme did remind me of the thing I was thinking of: http://www.ikvm.net/userguide/ikvmc.html
Personally, I'd say it is probably the case that there are better alternatives. Azure Document Intelligence being one of those. Sure, it can't handle the variety of formats, but again, we have to come back to the underlying assumptions: .docx, .pdf, and a few handful of formats probably covers 99% of business use cases. Everything else would be considered niche.
There are exceptions in the form of well-written community-maintained libraries, but these exist for minority of Apache projects and vary a lot between languages.
Luckily, there are often (but not always) plenty of alternatives to whatever it is that you seek from Apache.
Many of the first party libraries are really, really good. EF Core is a prime example of possibly one of the best ORMs on the market right now in terms of productivity, ergonomics, and performance.