I am playing around with a proof of concept test page right now. You are not the first person to request the feature, so I am doing some research on it.
This feature will be a LOT easier once the Wake Lock API is implemented in web browsers. But I am looking a work around library to implement it now.
The library browser relies on a LOT of AJAX queries and JSON parsing. Due to the way the API works, caching will not work. On quick devices like a desktop, it is more usable. But on a Raspberry Pi touchscreen, it can be sluggish.
The library browser is tough to program because of the constantly changing “item id” key in the JSON. This is the main reason why Roon Web Controller and st0g1e’s roon-extension-ws-player are the only ones I am aware of that have implemented a library browser.
Even on the Roon Web Controller client that I use on my desktop, I find that I use the search feature more than the browser.