Sorry you did the factory reset, that made a bad situation much worse. Hate to start off that way but if it gets someone else to not make that error their problem will be less difficult to recover from.
Maybe you can recover by going back to the basics.
Power down all Sonos
Reboot router and controller.
Power up and factory reset ONE Sonos, if any are wired to Ethernet pick one of them.
Add the freshly reset Sonos as a new system. If it doesn't update do that before anything else.
If it adds and works then power up and factory reset another Sonos.
Add it to your existing system, not a new system, and update it.
Once tested do the same for each Sonos, one at a time.
This is the original error, the recovery process there is voided by the factory reset.
https://support.sonos.com/en-us/article/error-1066-when-updating-sonos
it seems there is a problem with registering the new sonos, like somehow my router isn’t communicating with sonos servers. I’ve reset both router and devices.
so the 2 wired units, when I go to add them, says problem checking for updates and error code 1067
wired
I have a shaw modem/router all in one. That sends out a hard wire to 2 sonos connect amps. The rest are wireless
i am on a chat with sonos and they say they cannot see my system the entire thing is offline, but I have full internet. So crazy
Looking at your profile and the speakers/devices you have, I would suggest hardwiring the Beam and the Connect Amp, only if it is NOT used as surrounds. Sonos does not recommend using a Sub or surround speaker as the main connected device. See Here for more information.
Also, turn off any VPN, PiHole or additional router or extender if any are present.