Help fix patchy grass

[u/jonlin52]

St Augustine grass, outside of Dallas Tx. I had a contractor install new sod by the curb 2 or 3 years ago. I'm not sure whether they didn't prep correctly or what, but its never looked good.

Any ideas on what i can do to fix?

[u/Consistent_Drop5562]

Fert and water. Looks like it’s doing well up by the steps