FWIW, there are a few companies cropping up now doing better codegen for client libraries. I'm starting one of them: https://stainlessapi.com
Unfortunately we don't yet have a "try now" button, and our codegen is still closed-source, but you can see some of the libraries we've generated for companies like Modern Treasury and sign up for the waitlist on our homepage.
CTO of Modern Treasury here. We're very happy with the quality of the client libraries being generated by Stainless. It also integrates nicely into our workflow, we've got the releases almost fully automated whenever new API routes are added or changed.
Unfortunately we don't yet have a "try now" button, and our codegen is still closed-source, but you can see some of the libraries we've generated for companies like Modern Treasury and sign up for the waitlist on our homepage.
Always happy to chat codegen over email etc.