Are you using iOS or Android? The reason I ask is, if you have a spare Android device running Android 8 or higher. You can download version 1.8.07.23 from APKMirror. This version does not have any device limits. I’m sitting at 275 devices right now and ST’s will not let me add any devices to my v3 hub. I just grab my old phone, add the device and then switch back to my daily driver with the latest app to configure the device and set the driver if necessary. It’s a hack, but it works.