What I know about my RB5009, it support 10Gb at operates at a lower signaling rate (1/4) by using Mikrotik S+RJ10, this mean SFP+ support 2500base-T
Problem is, RB5009 didn’t support HiSGMII/2500base-X… RTL960x ONU SFP require intermediate RTL8221B chipset to convert HiSGMII/2500base-X to 2500base-T to fool RB5009 thinking RJ45 SFP+
There will be new ONU SFP called LXT-010S-H that rival V-SOL V2801F, CarlitoxxPro CPGOS03-0490 v2.0 at same price range! Industrial Grade with-stand 85°C at 24/7/365 runtime, with RTL8221B chip sit between RTL9601D and SFP+ Host that enable 2500base-T support, newer Linux kernel, wide support OLT profile to fake OMCI Info, EthUni (4-port ONU LAN Emulation), custom VLAN mapping, PVID and much more.