It's also a solved problem that literally no human should have to bother with anymore. Like it was solved with SOAP APIs back in the 2000's.
Not to mention the fact that documentation is still always hand-written - which can have mistakes or typos in it, then downstream developers will have to translate that into hand-written client code, which can also have those same mistakes or bugs in it. And when the mistake is corrected, the dev needs to go back to where the correction was made in the docs, re-read and interpret the correction and then correct their client code. With API specs and code generators that entire process is automated now.
Now imagine bringing together approximately 6 different APIs into a single app, 5 have API specs while 1 doesn't. Now 80% of your time is spent on that 1 API where you have to read the docs to keep your client code up to date. Oh that 1 API vendor doesn't bother letting you know when their API is updated! So you have to F5 their website every week! This is literally my life right now.
Anyway, in this case, it was my mistake not to read until the very bottom where they had an OpenAPI yaml spec link there.