Hello, @Iggyp06. Thanks for stopping by. Whether the apps can be moved or not to the external SD card is determined by the phone's software version and the app version.
It can happen that the new version of an app will no longer allow the app to be moved. Also, your phone's software will stop an app from being moved to the SD card if it is necessary for the app to stay in the internal memory so that they can work properly without any damage or lagging.