Good first step is just seeding clover where grass is struggling.
Clover isn’t a normal part of lawns anymore because broadleaf herbicide kills clover too. But there is zero reason to use herbicide on a fucking lawn anyways.
But you barely need to mow clover if it’s dominant in an area. It “learns” the height you mow at, and just stops growing taller than that.
Like a 1/4 of my backyard only gets mowed once or twice a season, and it looks green as fuck because it’s denser. That ground covers helps retain moisture in the ground, feeds bees and bunnies, and with all the bunnies, I even get foxes.
Plus clover produces nitrogen, so it naturally spreads to the poor soil and improves it because it can out compete grass and even weeds. Insisting on an “all grass, only grass” lawn is some boomer shit.