The first thing is not to use ridiculous numbers that don't apply to your business. The best thing you can do right now is to build a plan, not an idea. Your idea needs to go through several stages of planning and validation before anyone will be willing to work on it for you. They need to see that you have considered and conquered the risks, that you have built a marketing strategy and validated it, and that you have investigated and validated the fit for the product in the market.
Your addressable market is the number you should be thinking about now. It's not 1.5trillion.
A tech co-founder isn't going to be interested yet. Get busy on your research, write a plan, and make a list of all your assumptions. Test each assumption individually to find out how accurate each one is, and make adjustments to the plan for every wrong assumption. Figure out what is required technically before you start looking for someone with technical ability.
Specifically look for ways to start part of your idea that cost little or no money. This will mean they take time, but you have an unlimited amount of time before you start a business that would otherwise fail due to lack of planning. Look for small things that are part of your business model that can immediately start generating revenue so you can start building your own funds to continue development. Do some research about what makes platforms successful. It's different than what makes software successful.
In other words, no one will invest their time or money in your idea, but they will consider your enterprise if you have worked out and tested a good plan.
First of all I would get rid of your title. Trying to build 1.5 trillion dollar edtech platform. That right there just tells me you are a rookie and don’t have a proper plan or idea of what you are trying to accomplish and talking about. If I were a technical cofounder, I‘d skip you: Best advice is to follow what Paul Garcia said.
Write your business plan. Don't worry about being the "first" but rather the best. You share any of your ideas, you can assume you already have competition. So if it is good, you wont be the first for long, and no one cares about the first anyway. They care about the one who best meets the needs. And if you are watching Shark Tank, or sucking in all the Entrepreneurship glam out there, stop. Make it about hard work, good work, and providing something of benefit. You do that, the rest will fall in place.