@KevinO
You don't need to enter any 'DNS servers' into pfSense for it to have a work DNS for itself and your LAN network.
You don't need to change ANY settings on the main (and other) Resolver (unbound) settings page.
And no, you don't need to enter ISP DNS info anywhere. That's something of the past.
pfSense uses a resolver.
But, when you factory reset pfSense, and yuo said you are using a "Internet Cable Modem" so I presume : the default (after reset) WAN interfacec uses DHCP and that won't work for you.
Didn't you have to use PPPOE, and enter a user name and password so it can connect to your ISP ?
Btw : It happens, ISP can have issues, don't let that be a reason to start resetting stuff. You can't set up pfSense afterwards, as the ISP is 'out'. You can't be sure if you've setup up things correctly as the ISP might still be out, or it is on, but you are mistaken somewhere.