Development of company website

I run a fast-paced call center and need a single web platform that brings every HR and payroll function under one roof. The application must automatically collect attendance data, calculate payroll with all statutory deductions, and track individual performance in real time.  Beyond those core modules, the same interface should also let our teams chat, post announcements, manage tasks and events, plan holidays, approve leave, raise support tickets, and study internal courses. A visual company organigram and shift-roster planner are equally important so supervisors can see staffing gaps at a glance.   Key modules I expect on day one:   • Payroll processing   • Attendance and leave management (including holidays and shift rosters)   • Employee performance evaluation   • Team communication and announcements   • Task, event, and ticket management   • Knowledge base and e-learning courses   • Dynamic company organigram   Please outline the tech stack you propose, the timeline for each module, and how you will ensure data security and role-based access. A live demo or screenshots of similar work will help me decide quickly. MERN: reactjs, expressjs, mongoDB, tailwind css, notejs, typescript  I would like to know how long this would take and the cost, thanks.