I think the last part of your post is the key issue here for you. You say you want to do something remarkable, you want to go big? What do you mean by big and remarkable? I suspect you mean financially very successful and famous/reaching a lot people? Correct me if I'm wrong.
However, what if you find your passion and it's nothing ''big'' (big in terms of how you think of it now), like..mmm, I don't know...gardening?
Of course, I'm sure gardening could go big too
As Goddess said, you're lucky you have many ideas and you want to try things.
I think you're looking for passion in terms of a specific ''job'', but how about trying to find out what lies underneath it, what is a common denominator in all your attempts so far..is it being creative, building something from scratch etc'. Once you figure that out , you'll find that you can express it in many different ways/jobs and not only one. I've also read many people do that exercise ''find your purpose in 20 min'', (haven't tried it) maybe it can help you?
And how about you stop looking for it, I think it creates a lot if pressure, maybe adopting a more relaxed attitude about it would help you see and notice things you haven't noticed before.
Even if you have to accept a ''regular'' job for now, you can always work on something on the side, that way you don't have a financial pressure that your business needs to start making profit immediately. And as you explore different things I'm sure you may find a passion for something you didn't even dream of.
I've also been thinking about finding my passion, and the thing is why only one? Maybe in the next 5 years it's one thing and then something else.
Well, good luck.