There is no easy answer to crabgrass!
This weed grows and invades and reseeds easily.
Using a herbicide in among your flowers and plants is very difficult without the risk of killing your established plants.
Pulling and weeding is the safest method.
I just spent 4 hours digging up a strawberry bed that was invaded by crabgrass!
You can try to smother the crabgrass with newspaper and some gardeners use hot water poured on the weed to kill.
The hot water method I find make it easier to pull up.