Got the Cloud Gateway Fiber! Such a nice little device - was so easy to replace my UDM Pro (backup config, restore config - just a few clicks and it was back up and running!). Saved half the space on my shelf since the UDM Pro is so wide.
Starhub -> UCG Fiber (SFP+ RJ45 module) -> Mikrotik CRS304-4XG-IN (10GB RJ45 Port) -> EB810v + other LAN stuff.
After connecting that up - now have available 4x 2.5gbit RJ45 ports on the UCG Fiber, 3x 10gbit RJ45 ports on the Mikrotik, and with the EB810v chained off the Mikrotik I can use its 10GB RJ45 LAN port in another room.