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.

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

I use a self-hosted invidious instance, and despite the recent issues with Google trying to block them mine works behind Mullvad VPN.

I use the web app on desktop, and Yattee client on my phone/ipad

Self-hosted Invidious or public Invidious instances.

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