Start watering it soon. Put out some cat food or tuna cans and turn on your watering system (sprinkler or in-ground). Watch for the cans to fill up and time how long it takes. That is your baseline for watering. Water it that long once per week. Then mow every week. Watch for seed heads to form on that coarse grass and take some close up pictures. Get the camera about 3 inches from the grass. Seed heads make it much easier to identify a grass. The time to renovate would be in late August for you in NH. It is also the time to overseed with fescue seed if you have that. The color leads be to think you have Kentucky bluegrass. Grassy weeds, like what you seem to have, are hard to get rid of in a grass lawn. It usually requires renovation where you kill the entire existing lawn and put down new seed.

I've been there. Loved it! Plan on going again. Thanks!

Looks like annual rye ....or some type of winter annual. Either way, it will die off in the heat. You can get rid of it quicker by shutting the water off for a couple of weeks and mowing short. The "water starvation" will not harm the bermuda.

my guess was creeping bentgrass too, and thanks Iawniac I didn't know tenacity controls it because pretty sure Drive XLR8 doesn't. if it were zoysia then the was zoysia there before and its tough roots system stayed alive even though you overseeded cool season grasses. If you're lucky the zoysia will eventually choke everything out and give you full zoysia (it's super dense and drought resistant but it'll go dormant brown very quick in Canada, goes dormant so quick that it should have been all brown weeks ago there and you'd not have pics of green blades), looks too stringy and thin to be zoysia anyway my guess is still creeping bentgrass or similar. Do a google image search of creeping bentgrass and scroll to see similar pics of the plants pulled out like yours. CBG is a perrennial so maybe you can live with it, it should fill in dense too, so dense I just read some putting greens use it but those are mowed very often to create a tight nit and also would need lots of water to cut anything that low without killing it.