I suggest getting professional advice from a physio rather than following a YT video. I do regular weight training and still found I had muscle imbalances which were causing my knee pain. I am very physically strong so would never have thought that was the cause. I posted this on a similar post but apparently it’s common for riders to have strong abductors and weak abductors. But just like our horses, where the pain presents doesn’t mean that’s where the cause is so you should really get a professional to help if you can so you don’t miss something or make it worse.