Professional Tax Discussion & Knowledge Platform

Build a modern professional platform called Taxnote focused on tax law discussions, professional networking, and article publishing.
The platform should combine features similar to LinkedIn, Reddit, and Medium. Users should be able to discuss tax laws section-by-section, create professional profiles, publish articles, comment/reply, and interact within a clean modern interface.
Required features:
* User authentication
* Professional profiles
* Discussion threads
* Comments/replies
* Article/blog system
* Search functionality
* Notifications
* Admin dashboard
* Mobile responsive design
Preferred stack:
* Next.js / React
* TailwindCSS
* Supabase/Firebase
I already have:
* Figma prototype
* Logo/branding
* Platform structure
Please provide:
* Similar projects
* Cost estimate
* Timeline
* Recommended tech stack