Could be. I refer to all those as "fill in the blank" grass. It seems to be somewhere in that Crabgrass Johnson grass orchard grass quack grass family. They're all tough as nails. A consistent pre emergent schedule will make a huge difference, but when they get that size, 30 seconds with a shovel is your best bet. A basic post emergent will zap the little guys. Unfortunately there's no one-shot solutions to those guys

So should I cut it out, put clean dirt in, then try to put seed? Or jus leave it and deal with the weeds that grow till I seed in late August?

I put pre em down for the first time this year but I want to overseed in fall. How do I time that right with a fall pre em app?

Leaving it in will do nothing for you. Pull them at that size & fill the hole. When August comes, skip the preM & drop seed instead. Once it's established you can start the preM back up.

If it is 10-12" tall in a weeks time it is probably Johnson grass. That stuff grows like crazy. All over the pastures back home. It will eventually put on a head like sorgum when it reaches several feet tall.

it's definitely not that tall after a week, but what sticks out is the huge clump.