Before I moved last year, it was easy. Pre emergent.

I now have a new build that did not have enough sod put down last Summer. I chose to avoid pre emergent in my existing bermuda lawn, so that I could put down bermuda seed this week and finish establishing the lawn.

The crabgrass has appeared and escalated quickly.

I could use some advice on what I can do about killing crabgrass while trying to grow bermuda from seed this Spring.

If it's already growing, you're fooked. I would nuke it later and sod.

Are the soil temps in the high 60's/low 70's yet where you are? Bermuda won't germinate until then.
IMO, nuke the crabgrass with round up & aggressively spray until temps get higher... then seed.

Where are you located that crabgrass has already germinated and is growing aggressively?

If you've seeded, and assuming the bermuda has started to imbibe water or even germinate, you may just want to wait and do a postemerge treatment this summer

Can you grab one of those propane torches and spot treat (flame weeding). I typically burn almost a quarter acre each year around this time.

Seems to knock back the crabgrass and stickers really well. And the grass grows back remarkably fast, but in all transparency, it's not Bermuda so I'm not sure how yours would react. Since Bermuda grows from the soil up, I would think it'd work just fine.

This stuff called Drive XLR8 will kill it. It's expensive. It will also kill the crap out of St. Augustine so be careful around those lawns. I ordered it once off amazon but now they won't ship it to TX. My local guy ordered some for me. I have some to spot treat.