I view statements about "overconfident artists who post their sketches / overselling their cheap-looking art" on the same unhelpful level as the unreflecting advice "If your art is bad don't post it". Social media dynamics already caused enough anxiety among art community members

Moreover the perception of one's own art can really differ from what other people see in your work. There are great veteran artists with imposter syndrome who still consider their art 'not good' until this day despite the overall positive signals and feedback over the years.

Of course there are also artists who are just pretty self-critical in general or having less self-esteem due to their impression of competition on social media platforms when they compare their experience level with others, making it anything but easy to appreciate their own art.