The difficulty is that you can't reason yourself into having them, but must nurture them by other means. This used to be one of the primary goals of education, and is the primary value of a (proper) liberal arts education, as opposed to "critical thinking" skills.
The Stoics wrote about the importance of cultivating a contempt for pleasure. The Christians teach that you should "Love not the world, nor the things which are in the world" (1 John 2:15). Understood naively, these statements are a sure recipe for unhappiness and disaster. But properly understood, within a healthy aesthetic framework and with emotions trained in accordance to it, these statements obviously contain a large chunk of the secret to happiness and success.
I recommend watching this video for an extended introduction to this way of thinking: https://youtu.be/tX5e6eSkaMc
Behavioral cognitive therapy is aesthetics for beginners, or maybe "applied surgical aesthetics"
If a big choice is required, then first do a search of possible benefits, and vulnerabilities. Of what you would do if things went wrong, what the worst case scenarios are, and how to deal with them.
I made such an analysis when considering leaving graduate school to start a business, and it helped immensely in clarifying things.
You do ask a good question, as there are two separate questions in the quote from Epictetus: resolving upon a thing, and taking action to conform to it.
It seems OP had already resolved, they just needed to make the jump. The resolution stage has somewhat different demands.
For some, they may find that some factors preclude such a big jump. For instance, obligations to support a family, health issues, major consequences to failure and lack of a safety net, etc. If so, then the second part of the question doesn’t apply, as wishing for a different circumstance is merely a dream, not a resolution.
But, if your trouble is merely comfort and inertia, then slap your face with cold water and wake up. You only have one life. It is seeping away even as you read this comment.
If you want to do something else and you are not doing it, then comfort is your enemy. It lulls you into sticking with what is merely tolerable.
But you are dying. Focus on this, focus on the pain of that realization. It is this pain, this discomfort, that can let you resolve upon a change, whatever that may be in your circumstances.
Once you have resolved, then all becomes clearer. Save every penny you can. Discard comfort and focus on necessity, for the transition will be worse than both the comfortable present and the expected better future. Every bit of slack you can generate helps immeasurably.
Ask if you truly, truly want the change. Soul searching on your own with pen and paper is the best method I know, along with long walks.
If you do form this resolve, and truly decide you want it, hewing to this idea is what lets you break out of inertia.
If, everytime you consider loafing around doing nothing (or worse, you wind up working all weekend on something you don't care about to make your boss rich), you think "I've got ~2500 sunday afternoons left, maybe 2000 in good health, maybe 500 while I have young kids", etc you consider how precious your time is.
And what are you going to do with it then? I totally realize how valuable the time is. This gives me tremendous anxiety and fear of missing out - it's so precious after all that I have to use in absolutely the best way possible. But what this best way would be?
So I end up in similar analysis paralysis that the one who spends more time choosing a movie to watch then actually watching it does. Needless to say that he also enjoys the movie less - because he is not sure that he made a right choice after all. And after that he realizes that he just waisted double the amount of movie time to something that he hadn't even liked.
IMHO putting time/productivity/goals/etc. as your top priority is a mistake. Similar to committing to some ideal from your childhood for the whole life. Unless yours and your close ones' personalitiea are not factored in, this is just a way to delude yourself into "productivity" trap.
For what it's worth, I find that if I focus on either making things or doing things with others, I'm happier than when I just consume. But I'm not a life coach - just a guy who spent waaaaayy too much time in my 20's playing videogames, staying in a college program I hated and should've dropped out of, and doing rather little to change it, until somehow the fact that I am, indeed, going to die one day and it's sooner than I think and there's stuff I want to do before then, really clicked in my head (and never went away).
If you have grown up giving in to discomfort/pleasure, then you are conditioned to accept the same. It's harder now, but not impossible.
Moral letters to Lucilius/Letter 82
How did you? Just by reading Seneca, or was there more to it?