About 4 ~ 12 a day, though roughly about 50 ~ 60 hours a week.
A 4 hour day would be if I have some problem that I know has a good implementation, but I just can't figure out how to do it. Then it's better to just stop and do something unrelated.
Though then once the problem is solved and all the puzzle pieces fall together - and I can just work on implementing it, and refactoring it into a good solution - I can continue working on it without caring about the time.
But I don't have a lot of days where at the end of the day I'm like "Yess, I'm finally done working, now I can start doing something fun!" - The working itself is already fun, so that creates a different "Working vs Not Working/Having Fun" dynamic
There's a user made OpenAPI spec: https://github.com/MV-GH/lemmy_openapi_spec - You probably mean that one
I've had similar issues as you mentioned that the dev did fix - but yea, Typescript has less precision than Rust (the source) or the openapi spec. And the Typescript client is build for Lemmy-JS and not build an example for other language client libraries...
Though the OpenAPI Documents in C# and Java are based on reflection of the source itself, and Rust doesn't have Reflection like that... So it's probably difficult for them to add without manually maintaining the OpenAPI specs