Invidious is awesome, I use it for all of my youtube guilty-pleasure needs. I really wanted to help with the project when the original developer gave up and development stalled a little bit, but crystal is kind of an esoteric choice, while interesting in it's own right. Syntax looks simple enough but I didn't really "get" all the features and tooling based on the documentation available. I guess it doesn't help that messing with youtube is rather complicated when you can't use the API.