Does the Nighthawl D7000 work with Nighthawk tri band mesh 1800

> HI, I have the Nighthawk 1900 D700 [...]

   Some of that is close to an actual model number.  Look for "Model" on
the product label.  A model D7000v2 also exists.

> [...] wondering if it will work with the AX1800 [...]

   Like "AC1900", "AX1800" is a speed, not a model number.

"work" how?  Did you want to use the D7000[vX] as a modem, or what,
exactly?

   If you use a Wi-Fi 6 router, then you should have Wi-Fi 6.  If you
connect a Wi-Fi 6 router to your (unspecified) ISP through a (much
slower) DSL modem, then it's not obvious how big the benefit of faster
wireless would be.