I can assume that the above-mentioned features that you have mentioned for your platforms is the overall main features you will need right now, and as the platform or your business grows I believe you will need some more additional features in the future that's why I will recommend the Tech stack that will make your mobile and web app scalable, robust, flexible, User-friendly and secure at the same time and when you need to implement some new modules you can easily customize and enhance your platforms.
Tech Stack and process that I will use:
UI/UX design: Figma / XD
Front-end: React.js for website / React-native for App
Back-end: Laravel / Node.js Database: Mysql / Firebase
SQA: Testing methodologies, UI testing, Bug Testing etc.
Deployment.