What do you use to private watch YouTube?

Freetube on Linux, newpipe on android and maybe a private invidious instance.

Grayjay on my Android phone. I like that it supports a lot of different services, and I have subs on Odysee, Rumble, and Nebula (I pay for a sub there). I sometimes download videos for offline use if I'm going to listen on my commute or something (no point in using up data if I don't need to).

On my desktop/laptop, I just use YouTube directly w/ uBlock Origin on Firefox (to block ads) without logging in. I don't watch much YouTube on my desktop/laptop, and when I do, I'll just look for a specific video or whatever.

I also have NewPipe installed on my phone for when I want to find something specific (i.e. background music or something), because Grayjay's search kind of sucks.

Self-hosted Invidious or public Invidious instances.

https://github.com/iv-org/invidious

I use YT-DLP to scrip the download of vids I want to watch and it drops them into Plex for me. I set it to run every 4 hours.

Oooh, this is interesting! How do you get the script to get latest videos from your subscribers?
- So there's 2 files that go along with the main script: a config file and a download list.
  
  The download list file is literally a list of YT channel URLs and any time I want it to get new channels, I add to the list. Conversely if I get tired of watching a channel, I comment it out or just delete it. YT-DLP just traverses the list.
  
  The config is where the magic happens. That dictates how the file is named, quality you download at, location it's saved to, format, etc. You can incorporate SponsorBlock which is awesome and even DeArrow has an integration. I enjoy the logging feature so it doesn't re-download vids it's already snagged. Generally I'll tell it to get every video from a channel that's been posted in the last 15 days.
  
  My destination for the files is a YouTube library folder I set up in Plex. Plex sees it just as another TV-like library and it pulls the metadata from the files, which are embedded by YT-DLP.
  
  Hope this helps!
- Can't speak to his method, but the jellyfin media sever has a YouTube plugin called Fintube that uses the above downloader to integrate YouTube content.

Grayjay

youtube-local over a Mullvad (other services like Proton or IVPN are great as well) works really well for me

I use several of the suggestions above, but also for IOS (iPhone) I use “Firefox Focus” and it clears everything when I close it and I can watch ad free.

With invidious and in FreshRSS I use the youtube extension to use the embedded video player, you just need update this part of the code https://github.com/FreshRSS/Extensions/blob/master/xExtension-YouTube/extension.php#L153-L163
It easy just to replace for this:

    public function getHtmlContentForLink(FreshRSS_Entry $entry, string $link): string
    {
        $domain = 'www.youtube.com';
        if ($this->useNoCookie) {
            $domain = 'www.youtube-nocookie.com';
        }
        $domain = 'invidious.personal.com';
        $params = 'quality=dash';
        $url = str_replace('//www.youtube.com/watch?v=', '//'.$domain.'/embed/', $link);
        $url = str_replace('http://', 'https://', $url);
        $url = $url . '?' . $params;

        return $this->getHtml($entry, $url);
    }

The only change is to use $domain = 'invidious.personal.com';
And add the parameter quality=dash

Seems there's also this one https://github.com/tunbridgep/freshrss-invidious
but haven't tried it

NewPipe

Libretube with a vpn! Newpipe doesn't look great imo

I have a locally hosted invidious instance but increasingly I'm finding most of the creators I watch are on Nebula. I just recently discovered that Rifftrax has a presence there.