Invidious is just an alternative frontend, much like Piped. It's against YouTube's ToS but that does not need to concern you (in most jurisdictions, you can't get prosecuted for using or recommending a website that breaches a civil contract). The videos are still being pulled from YouTube's servers so only those YouTube will serve are available (albeit under conditions YT would not approve of, such as without ads, with free broader playback speed options etc.). However, the server's location can be used to bypass region-locked YouTube videos, which might be considered priracy.
Also, there are client-side alternative frontends like NewPipe, Revanced (modified official proprietary Android app) and Grayjay (with optional features like Subscription Exchange and Polycentric integration relying on FUTO servers).
Google is desperate to find a use for their image-processing AI. Skip that step and just use a normal halftone converter. I think the AI preprocessing does little more than posterization and maybe sharpening/edge detection (also available in most 2000s image editors on a crap PC).