Dreadnoughts the way to go.
1K... I'm thinking a high end SX dreadnought?
Yamaha FG7-series i think should be over your budget.
John Mayer uses a Martin OOO mostly, so you might wanna look for something that shares similar wood specs, but it won't be very cheap. Construction plays a huge role also, so no way you're gonna get a Martin tone even with the same woods.

I might recommend you to look for something with a spruce top and rosewood or mahogany back and sides. Ovankol should be good too. Body type Grand Auditorium or Dreadnoughts will be fine I guess.

I remember playing one of the FG series which has a rosewood back/sides from yamaha. Sounded pretty good. Great for strumming since its a dreadnought.

Hohoho, that's his OOO signature guitar

so what you'll be looking for is an OM shaped guitar, rosewood back and sides with spruce top. Thats as far as the wood goes, how it sounds will depend on the wood quality and most importantly how the guitar is constructed.
That you'll have to use your ears to decide.

But honestly? I haven't actually got hold of a OM/GC/GA shaped guitar that sounds good under 5k. Around 1k+ dreadnoughts all sound similar but pretty good, just that, high notes far far from what smaller body shapes can offer.

Many brands that offer at that price, prepare to walk and walk and walk and test and test and test till all the shopkeepers hate you.