I don't think he doesn't trust his own abilities, he probably thinks he's the bee's knees - the problem is he has a hilarious lack of said abilities and is as limited as they come, while being afraid of change/adapting.
I know a lot of people think this is a criticism for the football on show and to an extent - it is. A lot is thrown around like "Mourinho/Simeone/etc. also play defensively and win", but it's just flat out not true - they've adapted a lot to football down the years, they've changed their approach when they have needed to, they've played differently with the same players as they just prepare for more than 1 outcome, and so on, which Dyche at this rate won't do likely ever. It's like in any line of work - if you don't adapt to the new technologies/approaches/etc. you'll forever be the person who doesn't know how email attachments work.