It didn't have to be this way! Wikipedia used to host all of this information before they switched from a policy of inclusionism to deletionism [1]. Now, it's all been relegated to for-profit hellholes like Fandom/Wikia. I dream of the day that someone stands up a new nonprofit, forks Wikipedia, and takes it back to the good old days.
The autoplay videos are often videos of their affiliated streamers on Twitch as well, which artificially increases the "viewers" count of said Twitch streams (thousands of viewers just browsing their wikis). You'll notice fextralife streamers near the top of Twitch by a significant margin on some of the latest trendy games (New World and more recently Lost Ark).
I wound up blocking all those with uBlock Origin personally.
If it's about the fextralife wiki and its horribel twitch inclusion on every page, ublock can suppress those divs and the last line rewrites the css rule to be full-screen (if that helps)
probably better to block the source if possible rather than to use a cosmetic filter
live.primis.tech$domain=fextralife.com
Also, I had to disable Firefox's Enhanced tracking protection in order for the video to show in the first place (ads too).
The addon 'I don't care about cookies' seems to remove the ads after ETP has been disabled too.
I only learned about this wiki couple of days ago. Obv looking for the elden wiki. Not really a fan of fextra, as someone else confirmed here about their shady wiki origins which I didn't even know about.
One possibility is to move the wiki to different hosting that doesn't stuff ads everywhere. It can be done, and I've seen it done successfully. Fandom actually lets you export the full data for the wiki, migrating the community is harder than migrating the data.
[1] https://www.gwern.net/In-Defense-Of-Inclusionism