Sloping soil - process of leveling and need help

Good afternoon! Hi, I'm new here. Great site! We are in the process of adding lots of dirt to level our 32'x26' backyard. It has taken months to get the dirt ready for seeding (new construction had left all kinds of trash in soil).
My next problem is that my lot angles from 6" to 2' sloped on one side of my neighbor. There is a fence which is supporting the dirt, but I want to reinforce on my side. I was thinking of digging in and putting 2x10s the length of the fence and filling the dirt back.
Any suggestions? PS...its a condo, so I am limited in what I can do ie using cement or some more permanent fixes without board approval.... Thanks! Chris
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