You should use archive.org or archive.today links.
The best way to influence the Domain Authority metric is to improve your site’s overall SEO health, with a particular focus on the quality and quantity of external links pointing to your site.
You can use the Wayback machine addon to easily get archived links https://addons.mozilla.org/en-US/firefox/addon/wayback-machine_new/.
And a bookmarklet for archive.today:
javascript:void(open('https://archive.today/?run=1&url='+encodeURIComponent(document.location)))
FYI, if you’re worried about archive.today going down and references being lost, you can manually leave in the original URL by adding https://archive.ph/o/ in front of any URL, after you archive it. IE: https://archive.ph/o/https://sh.itjust.works/post/26060585 will redirect to the archived page, if it exists.
Lemmy adds a
rel="canonical"link to every post. Google should be able to understand that and make every page with the same canonical link go to the same page. I think other sites who have many domains with the same content, like medium, do the same thing.