Language switcher -- stay on page (v2)

I have two languages / locales: nl and en (nl being Dutch, en being English).

I also have an About-page, that has the slug about-us in en.

In nl, the page's slug is over-ons.

I have built a language switcher that looks like this:

<div class="i18n">
  <!-- This page in Dutch -->
  <li>
    <a class="" href="{{ current_uri }}"></a>
  </li>

  <li>
    <a class="" href="/en{{ current_uri }}"></a>
  </li>
</div> <!-- .i18n -->

This works for pages that have the same slug in nl and en, but said About-page has a different slug in nl and in en.

The code above switches between https://<domain.ext>/over-ons and https://<domain.ext>/en/over-ons, while that last one should carry slug about-us.

I've tried lots of things, but I can't figure out what to do:

{{ current_uri | locale == 'en' }}
{{ current_uri locale == 'en' }}
{{ current_url | locale == 'en' }}
{{ current_url locale == 'en' }}
{{ slug locale == 'en' }}
{{ slug | locale:en }}
etc. etc.

Hope anyone can point me in the right direction.