Paying money to learn how to trade and losing money when you start trading is a double loss although you have gained some idea on how to go about your trades but this wouldn't guarantee Profit. Just like you said as a beginner trader you can actually learn about how to trade from different sources like YouTube and PDF materials on how to trade. Relying on YouTube videos isn't enough and I wouldn't recommend you to take every financial advice they give you on that platform, instead learn the basics online and look for a mentor to teach you trading strategies, The only down side to this Is the fact that everyone taking mentorship classes would definitely ask you to pay.
When beginners initially try to trade, of course, they will be very likely to experience losses and it is true as you said when they pay to learn trading and experience failure when trading, then they will find two losses at once, but they already have a basic knowledge of trading, if we only rely on the material we get from youtube videos or the material we learn to trade, of course it will be very risky because not necessarily what we learn ourselves can be carried out correctly.
I agree with you, it would be better to have a mentor who can guide you in learning to trade, but it is certainly paid because it is impossible for someone to teach for free, so when choosing a mentor we also have to really know whether they have been able to get good results from the trades they do or they have not been able to get good results when trading.