Answer 1

Impostor syndrome is not about your true skills, but your own insecurity and doubt whether you're good enough.
I think this can affect anyone, not only self learners. Software development is a creative job: every time you have to come up with new ideas and solutions. In addition, it requires constant learning and adaptation to new technologies, even for senior sw engineers. You are never "done" learning. So it is natural that there are some things you don't know, some situations you have not encountered. If you are prepared to face these scenarios with courage and confidence, knowing that you can research and find the answers, you can overcome your doubt.

I think a supportive and encouraging work environment is very useful here, where you don't have to be afraid to ask questions without looking like a fool. It is certainly better to have doubts, rather than being overconfident and messing up big time in the end.

Answer 2

I’ve never experienced that. Self-learning isn’t bad. You can learn the same that a teacher can teach. The most I know about programming is thanks to this platform.
I think that never and never an user have to be affected in any way for being self-learner. It is true that some self-learners have more experience and are greater programmers than others in informatic degrees…
It depends on your effort while learning.