Yes I agree on everything you said. We all become what we think so if we think lowly of ourselves then we will be lowly indeed. We must be able to change our thinking even if at first the positive thing we think of ourselves is not true and we may not believe it but saying it to ourselves and thinking it more often may somehow help use to be able it to change our outlook in life moving forward.

I'm not familiar with the imposter syndrome for artists but if we stop comparing ourselves to other artists we will be able to appreciate our own art and others too. :D