Sounds to me like you are mowing too infrequently and possibly scalping
lawn when you do. Then you need premerge for crabgrass, fall reseeding
and need fertilizer.
Ground cover needs care too and a well established lawn, cut once a
week at the proper level is not that hard to maintain. I have a
neighbor that struggles with his, letting it grow too high before
cutting. Takes him much longer and he must bag clippings for garbage
man. Frequent cutting and mulching clippings, only takes me 1.5
hours/week on slightly less than one acre very slopey lot.