How to use css next sibling selector with cached element

I have a cached element and I wish to use that reference to find the next (sibling) element in the DOM tree. Is this possible?

Initially, I thought this could be a use-case for the new :scope rule, but I was reminded that the scope rule only applies to descendent elements (i.e. desired element must be a descendant of the cached element).

const aa = document.querySelector('div');
const bb = aa.querySelector(':scope + aside');
//const bb = aa.querySelector(':scope > aside');

console.log(bb.classList[0]);

<div>Div<aside class="zoe yip xin"> span</aside></div>
<aside class="abe bob cam">Aside</aside>

So, how would one do this?

I am starting with a cached element – how would I use myEl.querySelector(blah blah) to get the sibling of that cached element?

For those desiring, here is a snippet with which to fiddle.

= – = – = – =

Note: I prefer not to use the parentNode or such, since the cached element is reasonably easy to find (has an ID), whereas its sibling (desired element) would be quite difficult to target from the parentNode.