Yep. I agree in practice Solid has some work to do here. The basics are think are reasonable in that we are dealing with your expressions in the template and real DOM nodes. So just drop a breakpoint in that sucker. Sort of return to how simple that was in jQuery/Backbone days.
It never is that simple mind you. I have an open issue around Dev Tools etc... We need to do better given the expectations of modern JS libraries.
With new projects and languages and frameworks a good angle to evaluate is, "what's the debug story like?"