Chiebukuro is a site many answers have referenced in the past, and very helpful, but since February 1 2022, it is no longer available in the EEA. This leaves a lot of sources on answers inaccessible to European/UK users (without VPNs); is there anything that can be done about this?
To clarify, we're talking about hundreds of posts (if that query is correct).
Stack Exchange staff has a simple tool to mass-replace links (even without bumping posts!) but all it can do is find and replace, say,
chiebukuro.yahoo.com if that would work.
The workaround you describe, saving the page as a snapshot in the Wayback Machine, and using that link, is something that can be automated. I've got all the parts ready (I have various scripts repairing broken links and images across the network), but it would only suggest edits, which then bump the posts to the front page. It does have configurable rate-limiting. And I need to find another place to run it from, since I'm located in the Netherlands ...