this won't help in terms of physically using the switch to save a pre-set brightness but if you set up a scene via the app, then the brightness gets saved when turning on/off with the app or using alexa/google home voice commands.
for example, let's say you are installing the dimmer switch in the dining room...
1. name the switch "Dining"
2. set up a scene called "Dining Room"
3. in the scene, add the "Dining" switch and set the brightness.
now whenever you use the scene, the lights will use the brightness level used in the scene.
when you integrate with alexa or google home, add the scene and when you say "alexa/ok google, turn on dining room" - it will utilize the settings in the scene itself.
only issue using alexa/google home with a scene, there's no "turn off" for scenes so you'll have to turn off the actually device, so you must say "turn off dining". or set up another group (with a different name) like "Dining Room Lights" and add the "Dining" switch. then you can say "alexa/ok google, turn off dining room lights".
a bit of a pain to remember to use one name to turn on and another to turn off since there's no "alexa/ok google, turn off <name of scene>"