Example for Starhub/M1 2Gbps connection (but I do not recommend the average users to connect the personal device directly to the second ONT port, because of potential security issues)
Starhub 2Gbps plan connection scheme
M1 legacy 2Gbps plan connection scheme
MR legacy 2Gbps plan is also a dual 1Gbps plan.
On the other hand, Singtel 2Gbps plan uses ONR and the 4 LAN ports of the ONR will work for internet access (or Singtel TV box).