Anyone that know's me knows that I'm quite familiar with the dark arts. I've even used hypnosis to con Christians into Atheism a half dozen times. The tempting idea is that dark arts can be used for good - and that the ends justify the means. I've since changed my mind.

The thing is, even though I don't advocate dark arts for persuasion let alone rationality, I almost entirely agree with the actions you advocate. I just disagree strongly with the frame through which you look at them.

For example, I am heavily into what you call "changing terminal goals", however I disagree that I'm changing terminal goals. If I recognize that pursuing instrumental goal A for sake of "terminal" goal B is the best way to achieve goal B, I'll self modify in the way you describe. I'll also do that thing you frame as "being inconsistent" where I make sure to notice if chasing goal A is no longer the best way to achieve goal B, I self modify to stop chasing goal A. If you make sure to remember that step, goals are not sticky. You chase goal A "for its own sake" iff it is the best way to achieve goal B. That's what instrumental goals are.

The way I see it, the difference in motivation comes not from "terminal vs instrumental", but from how you're focusing your attention. In what you call "instrumental" mode, you aren't focusing solely on your instrumental goal. You're trying to work on your instrumental goal while you keep glancing over at your terminal goal. That's distracting, and of course it doesn't work well. If it's a long term goal of course you don't see immediate improvements - and so of course you lose motivation. What you call "hacking my goals to be terminal" I call "realizing at a gut level that in order to get what I want, I need to focus on this instrumental goal without expecting immediate results on my terminal goal"

But there are also downsides to allowing yourself to "fool yourself". In particular, through that frame, the thought is "it's false, but so what? It's useful!". That stops curiosity dead when you should be asking the question "if it's false, why is it so useful? Where's the mutual information that allows it to function as a control system?" and "what true beliefs do better?".

For example, your "nothing is beyond my grasp" belief. It's empowering, sure. Just because you recognize that it isn't technically true doesn't mean you should deprive yourself of that empowerment - of course. However, lying isn't necessary for that empowerment. The problem isn't that you believe you're defeat-able. The problem is that you fear failure. So instead of focusing on the task at hand, you keep glancing over at the possibility of failure when you should be keeping your eyes on the road. One of the big take home lessons from studying hypnotism is that It's always about direction of attention. Strip away the frames and motivations and look at where the attention is.

My version or your empowering belief is (to try to crudely translate into words) "I want to succeed. I might not, and if I don't, it will be truly disappointing. And that's okay. And even though I might fail, I might not and that would be truly amazing. So I'm going to throw myself at it without looking back". And my version is better. My version is more stable under assault.

My wrestling coach would spout the cliche "If you can't believe you'll win, you wont!". If I had bought into that, the moment reality slaps me in the face I'd lose grasp of my delusion and crumble. Instead, I laughed at the idea. I went into matches already accepting defeat and focusing on winning anyway - and it allowed me to win a few matches that no one thought I could possibly win.