@tldr
When you're trying to bring something new into the world, and the path is somewhat long, there is a useful art of counterbalancing yourself.
If you ever feel like you are losing faith in your vision from critiques or potential problems, maybe listen to Jonny Ive talk about the delicacy of new ideas, and how a critic pointing out a problem does not invalidate the idea – an idea by definition has material elements that are unsolved, so it is extremely full-of-holes. By nature.
However, if you are becoming pretty self-satisfied about your mere idea, maybe listen to PG talk about how the only thing that matters is whether actual people are actually loving what you actually built... and how much manual work goes into merely getting your new thing in front of people, let alone making it worth telling their friends about.
(The best counterbalances are always actions, not just the consumption of advice; but often it helps to get in the right mindset to begin a counterbalancing action.)
How are you leaning now?