Currently there are no other roles a UiPath App author can assign to others who want to use their app other than Co-Author which will then give the assignee permission to edit the app itself. These steps are a workaround that allows the app author to provide "run only" access.
Inside the UiPath Apps section of cloud, you can edit the apps, assign permissions and run them, if you are an app creator or apps administrator , you can edit and run if you are assigned as co-author to an app, but aside from these roles, there is no other way to run apps from the UiPath Apps section unless you have these roles, and there is no other place to access it if it is not a public app. Apps - Permission Management
For the rest of the users to be able to have access to run an app or even see it, the workaround for this scenario is to deploy your app to a folder, this way, any user assigned to the folder should have access to run and see the app but not modify it. Managing Apps - DeployingApps