A sidebar with transition and a vertical scroll (css/javascript)

We have a site that uses CSS (mostly extended for Bootstrap4) and Vue3. We need a sidebar "relocated" on the page, it made sticky to the top when you scroll down, and the rest of the page be responsive to it as you open and close it. It should transition by "growing".

Also we need a horizontal scroll that scrolls left and right when the horizontal menu gets to big. Should not simply be a standard scroll bar (see images for the sort of thing I mean).

Whilst the site isn't regularly used on a mobile devise, it should still do something sensible in that case.

Most importantly it should look good and be reliable with minimal code!