Well, the bushes have been removed, and that alone is a massive improvement.
We have stairs!
Then I drew out the line I wanted to follow for the first retaining wall:
The top walls progress:
I'm not going to lie, building a retaining wall is zero fun. Making sure each stone is level takes forever. I'm really not looking forward to the one I'll have to do where the timber starts. But it will be worth the time and foul language spent.