Wait, you want a part time job on top of your full time so you can fund the startup with the extra money? Or you want to quit your full time and get a part time job so you can survive while you build?

Option A is almost certain failure as you'll never have time, Option B is not uncommon but still can be hard and not work out as well as you think. I'd suggest Option C, keep your full time gig until you get some traction with the project and get it to a point where jumping off the cliff is manageable. Then take on some consulting every so often to help pay your bills but devote almost all of your time to your project.

I am nontechnical so the consulting part would basically mean I do lead generation for a company or do sales for them, but super hard to get clients because very saturated, loads of sunk time searching for clients. I was thinking of Option B, quitting my full time, get a part time and work on my job the rest of it. Another commenter said Door Dash and Uber is a nice option, but I am fine with it as long as I can work on my project a lot

Fair, non technical means consulting can be harder (unless you have established creds) but also leaves you open to doing lots of other misc part time jobs. If you are in a major urban area Doordash/Uber/Lyft etc might be viable, but if you are in a more suburban or rural area not so much. Only you know the answer, it isn't a bad option if you can make enough to support yourself and invest in your project. The more time you can put on your project the better but it has to be balanced with not over stressing your personal life since one will affect the other. Good luck!

Driving for Doordash or Uber Eats might be a good option. Lots of downtime at night, you could bring your laptop along and work during the gaps.