Hi, there.
I 've checked your project description and requirements carefully.
My opinion is as follows.
Your project can be divided into two main parts.
First part, as a frontend, the mobile app can be developed as Native or Hybrid.
If you want to reduce your budget of this project, I prefer Hybrid.
As a hybrid, I can use frameworks such as Flutter, React, and ionic.
Second part, the backend can be in B2B or B2C format and can use WP, Laravel, or CI frameworks.
If you give me a chance to work with you, I will provide you with high-quality work only for you daily.
Please contact me and let's work together.
Best regards.