To have an client app on Android Tablets and desktops to access your Android phone Would highly suggest using Flutter or Tauri. Flutter and Tauri allow you to create an app and compile it for desktop, Android and iOS. Personally I think Tauri would be best since it is like Electron which allows you to use HTML/CSS/JS for front end app development and can compile apps for desktop and mobile.

With a client, no need for using Plain App in the browser and can install the app on your Tablet or desktop and always have it running in the background connected to your phone.