I think most of the time if they have a Github/Gitlab repo open to the public opening issues, they will accept an issue that merely describes a problem that needs to be fixed along with how it might be fixed.
Something like this is generally appreciated:
I'm an HCI expert and ____ should be improved to do ____ because of ____. I'm willing to volunteer to do design work on this to help the project out
...and if the maintainers ask for contact info, provide it and there you go.