hello folks, I hope you're all good.
I'm a Web developer, and I'm working with custom elements these days.
I've been using them with forms, and have been successful using formAssociated and ElementInternals to make the inputs in a shadowroot properly expose their values to the wrapping form.
But I couldn't find an easy way to make a custom element behave as a submit button for the form.
The goal is to get all the default form behaviors, especially related to the implicit submission when pressing "enter" when the focus is in an input, but also possibly other behaviors that I don't know (I'm thinking of accessibility-related things, or the new dialog and popover-related features).

I tried setting the form property on the button itself, but it's read only.
I tried setting setFormValue on the element's internals, but that didn't work.

Is there something I've missed in the spec? Or should I file an issue to explain this more (with an example maybe)?