>>106312410
I'm actually working on a project related to stuff like this. Here are some tips:
>You can install the Filmot Title Restorer (using Violent/Tampermonkey) to find privated/deleted video info, but it's quite limited due to API issues for recent (past few years) videos: https://greasyfork.org/en/scripts/430202-filmot-title-restorer
>>106312592
The tl;dr is that you likely won't be able to access privated/deleted videos though. You can find metadata, but that's about it in 99% of cases.
>>106312618
I've started archiving some YT channels use yt-dlp with scripts. It's crazy how many decades old channels are getting wiped because of minor transgression. It sucks how much centralization due to web 2.0 (thanks boomers) has crippled the modern internet.
>>106313193
I forgot to add the obvious, namely that sites like Rumble and Odysee can sometimes have backups of certain videos that regular users re-upload, but again, it's a solution that rarely works.