NewPipe does have a Share function for any video and there is probably some way to customize it to get the integration with your Linux laptop that you want. I believe (though I haven't tried in a while) that if one is watching a video on NewPipe and then clicks Share and passes the video to a media-center device running Kodi, Kodi will even start playing the video from that same timestamp, so Share is pretty powerful. Not sure what is available for passing vids from a Linux computer to NewPipe on the phone, though.

To add to the list, if you share the link over kdeconnect and select a linux device (mine is hyprland on archlinux) it'll open the link using the default $BROWSER. If there's a simple integration to sync subscriptions I think I'd give it another go. Fennec is good but as mentioned background playback stability would be really nice to have.