Real time note app for team collaboration

I am looking for a developer to create a real-time sticky note app for team collaboration. The app should allow multiple team members to collaborate on notes in real-time. The most important features for the app are real-time syncing, collaboration tools such as comments and mentions, and organization and categorization options. The app should be cross-platform, available on Web, iOS, and Android. The app will be used by more than 10 team members. The ideal candidate should have experience in developing cross-platform apps and be familiar with collaboration tools and real-time syncing.

Team members should be able to add sticky notes, group, add comments, etc.

Examples include the basic team collaboration features like figma, mural, miro, idea flip.