Best Modem for Orbi AX6000 RBK853

I am planning to buy an Orbi RBK853 system; my home is approx. 5000 sq. feet. I currently have Cox Gigablast. I need to get a new modem (as I am renting my current one).  What is the best modem to buy, especially if Cox upgrades service to more than 1 gig.   I'm thinking a Netgear might be best for compatibility with Orbi, but maybe that is not an issue--any thoughts? Also, is there any point in getting a modem with a router, or would it conflict with the Orbi router?  Thank you!