Is this brown patch?
We cannot tell from your photos if this is brown patch. We see dead grass and some weeds. There could be several reasons why the grass died such as brown patch, a summer disease of cool season turf https://extension.umd.edu/hgic/topics/brown-patch-lawns, annual and perennial grass species that may have died out, poor drainage, poor soils, etc.
If you have not had your soil tested in the last several years, we recommend a soil test. Results will give pH, liming, fertilization, organic matter, etc.
Now through mid October is the time for overseeding with recommended turfgrass cultivars. Here is our page on overseeding into an existing lawn, fertilizing, and care and maintenance after seeding. Fall is the best time to fertilize a cool season grass. https://extension.umd.edu/hgic/topics/lawn-renovation-and-overseeding
and our Lawn Maintenance Calendar https://extension.umd.edu/hgic/topics/lawn-maintenance-calendar-maryland-home-lawns