Such a person just can't develop, and his knowledge is only limited to basic knowledge.
Indeed. IMO, they are real example of failed traders but they are not aware about it. There are some people who only wasted time in trading, they never be real traders. Real traders should be the people who keep improving their trading knowledge.
After all, who is interested in beginners who only know the basics, but if he insists on becoming a mentor and provides the services of becoming a trading mentor, then ask how his portfolio is and whether his achievements are good enough on some of the trades made.
Sometimes it is not really easy to prove someone's capability in trading. Even he showed portfolio and his achievement, it can be fake proof. Also, it will be impossible that a professional trader shows his real trading account data (to ensure he doesn't lie). This just indicates that he isn't professional enough. The reasonable way to get a proper mentor is to join a channel of popular traders. But this way will never have fully lesson from the mentors because they actually don't give the lesson for us privately.
There are many reliable sources, but also many more sources that just make up nonsense.
I also do it self-taught, but in some histories I also learned from my friends who are already experts and professionals and joined several Telegram groups that are free for the public, but discuss details about trading and technical and fundamental knowledge.
Yep, that's why we need this forum, a place for discussing and finding out the information of proper sources.
Well, you're lucky, mate. It is good that you can learn from your friends who are experts/professional traders. Unfortunately not everyone is as lucky as you. By the way, joining the trading groups in social media are mostly intended for discussing and sharing information. It is not proper place for newbies who wants to learn basic knowledge.