Regiment, regiment regiment.
Feed breakfast, take out for walk, return home, put radio on, give frozen kong with peanut butter or yogurt before you open door to leave. Keep doors to bedrooms, bathroom closed. Sometimes dogs don't know what to do with all that space. His safe space should be the same everyday.
Humans: get dressed, pick up keys, open door, leave.
In the long run a midday walker will calm everyone down. Dog looks forward to walk, humans can breathe easier.
Freeze 2 kongs one for morning and one after midday walk. Good luck and keep us posted.