Hi @smith . Is this the Archer C1200 (AC1200) router for FTTP? Question to ask TPG is whether the router in its TPG-supplied form can accept a firmware upgrade of the standard firmware from TP-Link. If not, you may not be able to access features disabled by TPG: VPN, backup and restore of configuration, or get future firmware upgrades. This router doesn't support analog telephone connection.
In the user manual, I couldn't find a reference to VLAN ID which isn't used in FTTP, but might be needed if your partner's connection type is other than FTTP, but it also depends on the ISP whether VLAN ID is used.