As a quick test, I searched for the name of one of my favorite game series: "Baldur's Gate" (on its own, no qualifiers, properly spelled - I would usually spell it "baldurs gate" on Google, but I decided to give this one the best chance). I search for info around video games a lot, so that's quite representative of a good chunk of my web searches, and I pretty much know the top sites Google would give me for that query (on its own, without any further qualifiers).
The results were all either barely relevant, outdated (sites that covered the game back in the 90s/2000s before it was re-released), at best tangentially relevant or complete garbage noise. Some of the most highly relevant pages (such as the Steam store listing, the fandom wiki, the publisher/developer's forums for the re-releases, the Baldur's Gate 3 website and the subreddit) were not included at all. Those are all fairly text heavy by any reasonable standard, so I assume they were "punished" because they use JS? Would make sense that nearly all of them are way out of date.
Then I searched specifically for "Baldur's Gate Wiki" but still out of luck - some results, but nothing vaguely Wiki-like.
Finally I searched for "Baldur's Gate Fandom Wiki". This is basically "search engine easy mode", by giving essentially the name of of the site I am looking for. I got ZERO results. At this point I gave up and decided that this thing is useless.
Look, I'm all for unearthing good long-form content (in fact I would say that much of the content around this specific game would qualify), and I do get as annoyed at modern SPAs as the next grumpy neckbeard.
I think considering both of those in a search engine is not a bad idea in and of itself. But I have to wonder what's the point of a search engine that weights some arbitrary aspect of web design higher than the relevancy of the subject matter (to the point of not returning any results at all)? In fact, considering that generally speaking more recent websites tend to include more scripting, you are intentionally skewing the results towards (very) old content, which is probably doing the user a disservice.