I don’t know about “elegant,” but a fairly simple way to handle it would seem to be a redirect page at that subdomain. So create a virtual host of upload.ecowez.be, and have its index.html be:
<meta http-equiv="refresh" content="1; url=https://drive.ecowez.be/index.php/s/2bP3apPYZJiCSFr">
window.location.href = "https://drive.ecowez.be/index.php/s/2bP3apPYZJiCSFr"
<!-- Note: don't tell people to `click` the link, just tell them that it is a link. -->
If you are not redirected automatically, follow the <a href='https://drive.ecowez.be/index.php/s/2bP3apPYZJiCSFr'>link</a>.