After drilling they will use a white semen to cover holes. Of course wiring kena expose & visible if not how to connect to the BTU lah 

From what in understand about unifi:
VLAN400 for voice
VLAN500 for internet
VLAN600 for IPTV

First of all, I dont care about the voice service .
Currently I have a Ethernet cable attached directly from the VLAN500 port to wireless router in the middle of my house for maximum wifi coverage.
I also have another Ethernet cable attached directly from VLAN600 to another end of my house where the TV resides in the living room for IPTV.
I believe this is the standard Unifi setup. Both these cable are nicely concealed inside the wall.

If i would like wired connection for gadgets around my TV too (e.g. PS4, nVidia Shield, TV for Netflix, Netgear Arlo base station etc). My thought is to purchase two switches, 1 placed next to fiber optic modem, 2nd placed next to current IPTV set top box.

1st switch placed next to Fiber optic modem:
Fiber modem VLAN500 -> Switch1 port1
Fiber modem VLAN600 -> Switch1 port2
Switch1 port3 -> Wireless router through concealed ethernet cable
Switch1 port4 -> Living room 2nd Switch Port1 through concealed ethernet cable

2nd Switch next to IPTV set top box
Switch2 port1 -> IPTV set top box
Switch2 port2 -> PS4
Switch2 port3 -> nvidia Shield
Switch2 port4 -> Netgear Arlo base station
so on and so forth.

Is there any GBe switches that doesn't strip off the VLAN tags?
in this setup, does the network traffic knows where they are supposed to go?
Ultimately, passing through the first Switch, does the wireles router gets the VLAN500 internet traffic?
Does my gadgets attached to 2nd Switch gets the routed traffic passsed back from the wireless router?
Does my IPTV set top box gets the VLAN600 IPTV traffics?

Please advise.

Sorry for my confusion. Need to clarify something first. In a custom router setup, does the traffic with VLAN ID 500/600 being handled by BTU or Router?
referring to case 1 and 2 here, which are the setup done by TM?

Case 1: Router handles the VLAN tagging
[attachmentid=8946276]

Case 2: BTU handles the VLAN tagging
[attachmentid=8946309]