@JimmyL
Steps such as trying the connection without the router are an attempt to troubleshoot the high ping. Beyond trying different things with the connection I don't know what else you could try to diagnose that. The main concern with bypassing the router however is the ONT itself. Because of how fragile the glass wire to the ONT is we don't want our customers to touch it in any way. For that reason if you are going to try testing without the router we suggest you unplug the Ethernet wire for the Internet from the router end and connect that to the device you're going to test with.