You don’t really need to know any Ruby to do Rails. It’s so much it’s own ecosystem that you’ll end up learning Rails-flavored Ruby no matter what you do.

That being said, vanilla Ruby is a real joy and you’ll be a better developer if you do take the time to learn it deeply. One fun source of lessons is Ruby Tapas, which is a subscription video “channel” that presents tons of best practices and neat tricks in short ~5’ videos. I highly recommend subscribing for a month and plowing through the back catalog :)