Slow and sustained population decline while automation and AI are increasing is great news. A gradual gobal population decrease would be beneficial in every way except for economies built on perpetually increasing consumption.
World population in early 1800 was around a billion. As recent as 1928, it was only 2 billion. We added 3x that number in the last 100 years!
I see population decline as a good thing. Nations should focus on managing the decline gracefully. It's good for the environment. It's good for distributing our limited resources equitably.