OK, let’s pull this apart piece by piece.

The Arc is currently connected to your router with an CAT6 cable, via an access point? And the Arc connected to the TV using the HDMI cable to a port that is labeled ARC?

Can you see the Arc in your Sonos controller device? Is it just the SUB and the two Ones that aren’t connecting/showing up?

What system did you take the Ones from? Was it your own system? Did you set up the Arc as part of a new system, or or did you add it to your current system? What speakers do show up in the controller?

Why did you factory reset anything? You should not have had to do that, but adding those devices back to whatever system is showing up on your controller should have been relatively easy. I’d add the two Ones back as separate rooms first, then assign them as surrounds bonded to the Arc. I think you should just be able to add the SUB directly to the Arc, assuming the Arc showing in your controller. 

It really would be helpful to know your network topology. If any Sonos device is connected to your router with an ethernet cable, it would benefit us to know what access point is involved, since Sonos is slightly picky about being on multiple subnets. If all your Sonos connects directly to your router, it would be helpful to know which router is in use, and if you’re using a 2.4Ghz channel, or a 5Ghz channel. It also might help us to know what device you’re using the Sonos controller on, and which version of the controller it is (S1 or S2, and which build) 

Would like to help you, just don’t yet understand how, quite yet. 

Can you explain how these statements reconcile?  What won’t connect to the Arc?

You say you have connected an HDMI port to the Arc.  As Bruce said, it has to be the HDMI-ARC port to the Arc.  Is that what you have done?

It might also help to know whether other sources play, such as internet radio.