Which SFP do I need for GPON networking

My experiments with the BPI-R4 are coming to an end, time to make it “just work”. The ISP has installed a ONT at my home (dumb bridge), where the router (which I am allowed to install myself but is getting outdated) plugs in with a RJ45 cable.
If (not sure when) the R4 pro is available, I’d like to use that to replace:

  1. the router / AP
  2. the 10/5/2.5gbe switch linked to the router
  3. the ONT of the provider, named ‘ONT-GPON-4PORTS-V3’

all by this BYOD piece of technology According to regulations, ISPs should allow to provide a method to replace the GPON ONT with your own if you want to (but off course they don’t like it). But, question arises: Which SFP GPON can I use on the R4 pro? I’ve had a bad experience with the SFP+ ports of the R4 when not carefully choosing modules. GPON networking is completely new to me, so does anybody have a suggestion what to look for when searching the internet for a GPON module? According to the documentation I have from the ISP, I need a single-mode optical fiber GPON module GPON info of ISP, but which one will be compatible with the R4 pro?