So you've got the hub 2 LAN side on the WAN side - so no NAT and so on, and just one device (the hub 2 itself). No - it won't work.
The hub WAN side is supposed to be on the RF connection (F type cable).
I guess if you put the hub 3 in router mode (not cable mode, whatever that is, or modem mode) you can use the hub 2 as a remote access point, connecting to an Ethernet port and turning off all the routing functions including DHCP etc. but I don't know for sure...
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I know a bit about Wi-Fi, Telecoms, and TV as I used to do it for a living but I'm not perfect so don't beat me up... If you make things you make mistakes!