Is it possible to see a list of the settlers in a given settlement and the jobs they are assigned to? It would make it easier to pick a settler for a new job.
The Vault-Tec Workshop added a buildable item called the Vault-Tec Population Management System. This let’s you management settler assignment to jobs as well as unemployed settlers. It also helps you keep track of companions.
To build it, you will find it in Workshop Mode -> Power -> Miscellaneous
If you do not have the Vault-Tec Workshop DLC but PC mods are an option for you then you can try the Don’t Call Me Settler Mod which provides settler management and a few more things like auto-assigning settlers to available jobs, clearing corpses from your settlements, and tracking damaged items in your settlement.