I'm looking for an app to browse YouTube using multiple accounts. It has to be convenient to switch between multiple accounts, and keep them separate. I've struggled to find a YT client that does this well, most of them seem to advertise "Use YouTube without an account". I'd look on the app store but frankly the play store sketches me the fuck out, even though google has a "moderation system" (we all know how well they keep malware off the platform)
What you're searching doesn't exist and will never exist.
You want to comment/interact with multiple accounts, and that can be done exclusively with the official app and the official website.
The reason is that if someone reverse engineers and spoofs a way to comment from a foss app, 30 seconds after the first release, some spambot asshole would immediately edit the code to send spam, and Google would patch that way immediately
Not really anything like this out there, Grayjay might work but I've never tried it. You could have two different ones, like NewPiped and Libretube, maybe?