Smothering the lawn with compost can be problematic.
The recommended rate is 1 cu yard for every 1000 square feet of yard.
The depth should be 1/4" of compost.
Any deeper and you run the risk of losing the grass.
You can try raking out the area.
You may want to have a lawn expert examine your issue.
They may be able to help remove and aerate the lawn.