I would like to know the best workaround in case if it's still unsolved

i myself don't face this bug but there are several reports of it yes. to workaround it try this

// Instead of
<Link href="...">Hello</Link>

// do
<Link
  href="..."
  onClick={() => {
    window.scroll(0, 0);
  }}
>
  Hello
</Link>

or the various window.scroll workarounds suggested in that issue

I see... I don't understand how/why adding an icon library can cause the scroll issue

It's not linked to the icon library, that may be causing it for some people but it's not for all. There's a minimal repro on the issue that doesn't have any deps and demonstrates the bug.

For both methods,
router.push (https://nextjs.org/docs/app/api-reference/functions/use-router#disabling-scroll-restoration)
Link scroll property (https://nextjs.org/docs/pages/api-reference/components/link#disable-scrolling-to-the-top-of-the-page)
The implication is that the default behaviour without any user interaction sets scrolling to top on a new route and passing scroll: false will prevent that behaviour i.e. maintaining the current scroll position on the next page. However the definition of a new route is crucial here. The behaviour I'm experiencing is scroll behaviour correctly going to top on a page never visited but when jumping between pages repeatedly that I've already visited, the previous scroll position is retained.

I've implemented a layout level scrollToTop bound to a useEffect linked to the usePathname hook but even that doesn't seem to cover all of the time.

I've had to forcibly put a scroll to top on the individual pages where I want to guarantee users are going to be scrolled to the top on each visit.