I finished The Gaulheim Hit in time for the deadline, and posted previews of act 2, Project Einherjar.
Being dissatisfied isn't any less wrong an outlook as being content with mediocrity. I can juggle statistics and feelgood writing philosophy, or I can bust my ass on my work and want it to be noticed -- either is fine, even if I'm not successful at the latter. I create things to entertain myself first and everyone else second, which is the only really good writing advice I can give, because otherwise the creative process is soul-crushing. "Just be satisfied with your own work regardless of how few readers you have" doesn't work for people who want to do it for a living, who have to actually promote their work every way they can so that it gets as many readers as possible to generate their income. I don't care about that someone who does it better than me, because their career is removed from my own; I care about whether or not I can actually make a name for myself. Maybe I never will because I write weird niche stuff.
It's okay to be content. It's okay to be frustrated. Either one is human.
Also, beware those bestseller lists people speak so highly of. They're an invention to sell books, nothing more. A lot of those books made the list before they were available to the public -- how can it be a bestseller if no one's actually bought it yet?