I've used VueJS/NuxtJS/Tailwind for the frontend and a NodeJS/ExpressJS/Postgres backend.
I've developed everything custom and didn't rely on a headless commerce solution.
it's amazing you built a complex marketplace/commerce site all from scratch. big kudos! if you ever do a paid course on your development, I am more than happy to pay!
Awhh, thank you! I don't have plans for a course, but feel free to hit me up on Twitter if you need any help or advice, haha.
Best way to learn imo is to just start with an idea and tackle one task at a time. Before you know it, you'll have a fully functional and impressive creation on your hands