Depends on your comfort with CLI tools. Here's the process (assumes Windows):

1. Download and extract platform tools
2. Add that location to your PATH

• Win + R, type "cmd", enter
• set PATH=%PATH%;C:\your\path\here\ <- Temporary, just for the current session
• setx /M path "%path%;C:\your\path\here\" <- Permanent

3. On your device, go to Settings -> About and look for Build Number it can sometimes be buried in Software Information

4. Tap Build Number repeatedly until a message appears You are now a developer

5. You should now have a new Developer options menu item somewhere in your settings. Sometimes it's top level, sometimes it's buried under Additional Settings or Advanced Settings or the like

6. Make sure USB Debugging is turned on

7. Connect the device over USB

8. Back on WIndows type:

• adb devices
• You might get a popup on the device asking if you want to allow USB debugging. Select Yes, and run adb devices again. You should see your device listed

8. Download the APK of the app you want to install (AAB files are a PITA, but can be installed too. Try to get APK files though)
9. Install with:

• adb install C:/path/to/app.apk <- if adb devices only returns one device
• adb -s <device_id> install C:/path/to/app.apk <- specific device

You can install updates the same way, just download the updated APK and add the -r flag adb install -r C:/path/to/app.apk

More useful adb commands