Have you considered directly contributing to PAPI and integrating the functionality there?
It seems useful from a glance, but i dont get the value in it being its own thing.

Thank you so much for the effort and the proposal, but as Oliver said before the new Polkadot-api aka papi (not polkadot-js api) solves this already. It feels like you are doing a lot of manual work, which doesn't scale in the long run, although we already have a fully typed and fully working api, based on the metadata, with no manual work.