I am somewhat familiar with both, UI/UX and keep relatively apace with a few fields of research. Currently, I'm working to become good at front-end development.
This is an area I'd like to work on, if you have a project that could use someone like me please hit me up here (a comment with your email) or via twitter (@_areoform).
We just wrapped up our very first community building event. https://github.com/SpeciesFileGroup/taxonworks_together_2020. You can track us down from there if you're interested. All our software is open source, and we have a ton of open issues ;).
BTW, I'm fairly certain that the "github submit a pull request" model doesn't work for UI/UX. Consistency and tone matters, as does integrating feedback and cycling it. The idea of hitting issues piecemeal without some kind of overarching strategy feels like a recipe for failure.
Unless you have unified brand guidelines, a UI component library etc, such an effort seems like an exercise in futility.
One possible way of interacting would be to explore the API, and develop a proof of concept UI element with a bit of functionality, that plays off it. Perhaps in a context like this: https://github.com/jlpereira/tw_api_test.
We do have use various semantics throughout the project, randomly documented. Contributions to how best to organize and get beyond this are also welcome, along the lines of this issue: https://github.com/SpeciesFileGroup/taxonworks/issues/85.
This is an area I'd like to work on, if you have a project that could use someone like me please hit me up here (a comment with your email) or via twitter (@_areoform).