Great text, Zoltan.
I created my first open source component when I faced some issues with select components which make use of many items in a dropdown way. Although native selects have different behavior on mobile devices (presented in a modal), they are very simple and often substituted by alternatives with more functionalities (e.g. filtering).
The most annoying issue that I used to have was what you said: “Scrolling through the options might be painful on some mobile screens where the visible and scrollable area of the list is small”. I adopted as the solution a little popup which comes from bottom of the page. You can check it out right here: https://stanleysathler.github.io/sth-select/example/. As a UX professional, what is your opinion about this approach?
More details about the component can be found here: https://github.com/StanleySathler/sth-select