Design an E-commerce site with a drop feature, customisable collection page and secondary marketplace serving both digital and physical luxury fashion.

Design a top-notch website that maintains flexibility to meet diverse designer asset needs, even in the face of tight deadlines and shifting objectives. Prioritise a visually captivating approach while ensuring an excellent user-friendly experience (UX). Implement key features like customisable collection pages, fiat payment, a secondary marketplace, and a seamless drop feature. Additionally, establish and deploy a brand guideline aimed at captivating new luxury fashion Web2 users, influencers, investors, and potential partners.