Users using multiple related apps

this is a simple question i just wanted the perspective of someone who has done it already.

we built an app for internal use at our company that grew into multiple functions with several data tables and became very unwieldy with large sync times. while we were able to mitigate some of this it was decided to break this app up into several modules and use a launcher as a main menu. the different modules still use the same spreadsheet in the back end for their database.

now that we are getting ready to deploy, what is the best strategy in terms of user access. the original app had a permissions table that held user emails with columns to designate what sub menus they had access to, we are taking a similar approach now. what is the best way to deploy, have users download each individual app (module) and install? with the modules it is alot more cumbersome and Im afraid will probably require our IT office to setup for each user.