I'm not sure how much time I'll have what with other projects, but I'd be up for doing a few PRs for some of these features too.

Nerdamer looks pretty interesting, the API seems like it would lend itself very well to auto-generating calculators.

A lot of web calculators have a "Enter any two values to solve for the third" UI, and with symbolic algebra, you could take any arbitrary equation and generate a UI like that, so it would be easy to manage a library of potentially hundreds of equations in a declarative way.

But there are a few other JS math libs that are similar.

https://nerdamer.com/functions/solve.html