Most devices will not allow category_num to be changed (they are reset upon rebooting)
Some devices may allow it but one should not change the category_num as this is what determines what the user interface uses to determine what controls to present to the user, especially in the phone app and may make the device unusable.
However subcategory_num change are configurable by the user and changes are saved (Commands, “Configure node right now”)
One can remove a device from the “Turn All On” button on the Dashboard by changing the subcategory_num above 3 (I use 8).
Not all devices work with alexa, no sensors , doorlocks, or window coverings.
On top of that if you add a new device to vera you need to let vera know you want to link it to alexa. To do that login to the controller using the browser, then before you select the controller, top right should be your name, click the chevron and select manage alexa.