Android / iOS based Core HR, Payroll, Training, PMS, Collections, Sales, live voting and alerts / messages

Want an excellent team who can develop a App based Core HR, Payroll, Training, Collections and Sales module. this App should be able to give multiple simultaneous connections, run the payroll on App, manage the compliance via App, Mark attendance via Geo fencing and Geo tagging, employee on-boarding on mobile, digital locker on mobile. a interactive dash board can be given on a link for preparing custom reports on the computer, rest all activities have to be done via app only. training videos and online assessment. this should have online chats and alerts, graphs and informative dashboard that is flexible as per user requirements. this should have customization workflows. should be able to handle multiple companies and multiple rosters. very important : all business logic to be on the server side and app should be able to run on low bandwidth or no internet and match up on return to network, should run on the lowest RAM on the device. User authentication and user role assignment, module based role assignment, the app should have audit trail on who did what and when. access level to be at App Level, Screen Level or Field Level. App should be able to run on lowest level of Android and iOS. No images or documents should reside on the mobile device. would like to have a month on month recurring support until project stabilizes after the free support period given initially. the entire code to be commented well and no private functions or proprietary encrypted code to be used, language preferred is "Flutter". code will remain my property. in case of discontinuation of the project, source code to be handed over immediately and any clarity anticipated to be given.