Netgear AC1750 serial number

> I have lost the card that slips out of my router with the serial
> number and password on it. [...]

   Which "password"?

> Model: C6300BD-1CXNAS|Docsis 3.0 AC1750 Cable Modem Router

   Is that accurate?  Cox is your ISP?

   Assuming that "-1CXNAS" is right:

      https://www.cox.com/residential/support/netgear-c6300bd.html

      https://www.cox.com/content/dam/cox/residential/support/internet/print_media/Netgear_C6300BD_UserGuide.pdf

   In the User Manual, look for "Types of Logins".  According to that
manual, this device uses Netgear's standard "admin" and "password" as
the credentials for the management web site.  If those don't work, then
a settings reset should restore them.  Look for "Factory".

   When you can access the management web site, you should be able to
see and/or change the wireless-network credentials (SSID, passphrase).