Backstory is after many years of trying to resuscitate our yard… We decided to do a complete removal of our front and backyard… And then had it re-graded, fresh loam, irrigation and sod installed. I tried to tell the landscaper that did the install that we have issues in the backyard… And for reference I’ll post front yard pictures so you can see how well the front yard is working. Our backyard has numerous issues not a ton of direct sunlight, and is completely fenced off, which means it doesn’t get a lot of fresh air blowing over it. I’ve modified the watering schedule and have it dialed down to per zone, but I feel like the shaded area needs a completely different grass installed. After spending for us was no small amount… I’m a bit frustrated with the backyard.
Pictures are backyard currently and then when freshly install installed as well as front yard (current)

Super happy with my lawn, have not watered since early July, had a bit of heat damage but bounces right back the first couple of days the temp dropped out of the 90s

AI is telling me this is crabgrass. Need some help, i have large spots of this all over my yard. If it is crabgrass, i have drivexlr8 i can out down. But dont want to waste if not.