Speed was promising. Using the bridge mode from the D-Link DPN3060V-B1 (Black Unit) to my TP-Link Deco BE85.

Is your D-Link DPN-FX3060V a white or black unit? If it's a black unit, set the Deco to router mode.
1) Login to your DPN-FX3060V WebGUI with the credentials below:
Username: tmadmin
Password: Adm@xxxx (xxxx is the last 4 digits of your MAC address of your D-Link ONU)

2) Go to Maintenance tab and backup the config first.

3) Make sure you have the Unifi PPPoE details with you.
Username: example@unifi
Password: xxxxxxxxxxxxxxxxxxx

4) Go to Wizard, Quick Setup, change the WAN Mode from GPON Router to GPON Bridge and apply changes.

5) Go to your Deco app, changed the Operation Mode to Wi-Fi Router. Insert your Unifi PPPoE details.
Connection Type: PPPoE
Username: example@unifi
Password: xxxxxxxxxxxxxxxxxxx

6) Follow the screenshots below to configure the VLAN settings.





7) Configure your Wi-Fi networks.


Hope it helps!

The white unit's max port speed is 1Gbps, so if you want to achieve the full 2Gbps speed, you should use the black unit instead.