I moved into this house a couple years ago, the lawn has gotten progressively worse. Last year I used the Scotts 4 Step lawn care and the lawn has never looked worse, I don't know where to start and may end up just forking over money to a lawn expert if I can't improve this...

The lawn is patchy and bumpy, I think the Scotts fertilizer "halted" the crab grass, but that just makes the patchy spots more noticeable.

Any advice? Pictures below. Thank you!