Browser Based Unity UI Input without implementing buttons in a WebApp

I may be missing something in the examples, but is there a way to present the Scene with Buttons to a web browser using an in Scene camera via RenderStreaming (either as a UI Camera target assigned to UIToolkit or a UI Canvas) and have the web browser send back X-Y coordinate based input? Motivation here is to not implement actual buttons via HTML as our button layout is being defined dynamically in response to state changes in our scene. Hoping to avoid passing JSON out to a webapp for dynamic button layout changes and handle all button implementations in Unity scene but recieve input from browser.

I could not get the above to work based on examples, wondering if I am looking at the wrong examples or have some other issue with my setup.

Thank you!