what's your ONT model ? Gateway-type ONT or Bridge-type ONT?
What does in service-port "tag-transform translate" does? Does it translate user-vlan 10 to vlan 100
// Yes, it mean translate the user-vlan 10 to vlan 100.
if so is user-vlan 10 in service-port same as ONT user-vlan? // Yes.
What exactly does translation works in srvprofile? To me it looks like it translates user-vlan 10 to SVLAN 10?
// in srvprofile, it means add the user-vlan to the eth port.