IMHO Your take on it has a faulty foundation, in part due to the way it's phrasing was proposed. At least, according to the linked discussion we were having.

Approach #2 should not say "an archive service run by SaidIt".

Rather it should say "a decentralized archive service discussed in a SaidIt subsaidit".

It may be called the "DIY_WebScrape_Archive" subsaidit. Within it everyone may discuss ideas and solutions, tips and tricks, recommend gear, share code, etc. SaidIt won't be running it, just hosting a discussion. The people will run it. There is no leader. I am Spartacus. Starting with "their" archive will be good but collectively we will figure out how to build our own decentralized archives with various protocols and various levels of commitment (ie. RSS or text-only archives are smaller than with-images are smaller than with-media archives).

If "we" run it then the only thing we have to fear is if "they" decide that we can't discuss it here. That's when the freeshpeaches go rotten. Before that happens we may be able to relocate to other safe havens like QxR where they discuss x265 torrents. But I suspect our regular speech is more of a problem than decentralized archival copyright issues, especially when "they" are doing it both secretly and at Archive.org without our permission - unless some dangerously damning stuff gets backed up and they feel compelled to go nuclear.

Separate from SaidIt this federation of archivists of individuals would be responsible for their own archives. They would have their list of trusted sources, including but not exclusively SaidIt.

I don't know exactly how this works. Obviously if I post "illegal content" on SaidIt I can be banned. That's not on SaidIt. Unless SaidIt does nothing about it. I don't know if there's a reasonable time limit or what the exact circumstances are, but I'd assume the same might be applicable to all members of a federation. If Bob is away on vacation or is too busy to check his email notifications that someone's been putting "illegal content" on his server, not only are the other members going to discuss this but they're also going to block Bob until he get's it together. If Bob is a weak link too often he'll be on special watch or ejected or brought down or become a crime boss in the underworld.

Also there may be ways to encrypt all the data others archive on your server like the old dark net FreeNet or I2P where you don't know what you have and you can't ever see it, while your backups on other servers can't be seen by anyone but you. Further still, you may only get incomplete parts of files, fragmented across many.

Now this is a hypothetical idea: There may be a way to authenticate some files. If several people agree the hash and the file are legit then it may not need encryption and it can be openly shared as "safe". Of course, with the equivalent of a 51% hack you may be compromised but at that point you're dealing with bigger organized fish that have somehow infiltrated your circles of trust.

This decentralized archival thing should be developed on Gitter, GitLab, or GitHub or whatev and also be for other sites beyond just SaidIt, in part to diversify and expand and overlap communities, and to take the focus off SaidIt. If Twitter is similar to Reddit in many ways, that means SaidIt is similar to Mastodon and that may be a great resource to help make this happen and to bring into our fold. Or not.