Build a Modern Client-Focused Service Platform (Shop + Forms + Membership)

I am seeking a web developer to build a professional, modern website that allows clients to browse, purchase and submit a brief for a range of business services. The site should feel clean, intuitive and premium, while remaining simple for both customers and administrators to use. Core Requirements: Category pages Individual product pages Custom briefing forms linked to each product Online payment processing Deposit payment option (50% upfront, balance due later) Membership area with gated content Discount codes and bundled offers Simple content management for adding/editing services and pages Mobile-responsive design SEO-friendly structure AI integration to summarise client briefing submissions for internal use Automation between forms, payments and customer notifications Future Features (Not Required Immediately but site ready) Blog/news hub Webinar registration and recordings Downloadable resources and toolkits Loyalty rewards Expanded member portal functionality The preference is for a scalable solution that is straightforward to manage without ongoing developer support. I have tried building in Wix but came across some challenges. I don't see this as a 'large' project that should take many months - but please quote what is reasonable for this site - happy to consider tiered recommendations.