Thanks for sending the diagnostic logs.
Based on the logs, your 2 iPads have the same client ID.
Currently, if spacedesk detects an identical client ID from 2 or more different devices, it will disconnect the second client instance.
To fix the identical client ID, one of your iPAd should have a different Client ID.
To do that, please go to one of your iPad’s settings -> General -> iPad Storage, find spacedesk, then „Delete App“ to delete the app data and cache.
Then go to Apple app store then reinstall the spacedesk.
Then try again with spacedesk and check if your 2 iPads can connect now.
Looking forward to your feedback.