I have had a love-hate relationship with YouTube for a long time. On the one hand, many channels put out great content that I want to watch. But the recommended videos feature is exceptional at hooking into my reptilian brain and getting me to waste a lot of time on junk that I later regret as a big waste of time.
I looked into a lot of alternative clients, including FreeTube, in an attempt to solve this. I use Tube Archivist[1], an open-source project that allows you to subscribe to and auto-download YouTube channels and playlists or download individual videos and watch them in a minimal web interface. It works fine on iOS as long as you set it up to download in an iOS-compatible format. I currently have it running in a Docker container on my Synology NAS.