Hi friend.
1. Whether the requirement can be met depends on how the upstream DBA of the OLT is configured. If the fixed bandwidth or guaranteed bandwidth is configured, a large number of PON port resources are occupied, and the number of ONTs connected to the downstream is limited.
2. Whether the ISP service can be used depends on whether the VLAN configuration matches the ISP VLAN configuration. If the user wants to use the ISP 1 service, you need to configure the line from VLAN 1 of ISP 1 to the switch to the OLT and then to the ONT.
I do not know the current OLT configuration and the number of connected ONTs. Therefore, I cannot provide a detailed solution. I can only provide the preceding suggestions.
Thank you!