Hello Dear, I've read your project description and I can create a custom extension of Flashexpress with Magento 2 as per your requirements. Let's have a quick Chat about the project.
We have extensive experience in designing and developing Portals, Web and Mobile application, E-commerce, etc. in all major platforms.
I am sharing our portfolio with you have a look,
https://www.freelancer.com/u/junkyfunky
Thanks,
Faizan