Xbox One party chat problems with eero router

Okay, so I have an eero router. I have two Xboxes. I was previously getting a moderate NAT on both Xboxes. I've port-forwarded the multiple required ports on my first xbox. I had to change the port on my other Xbox and I forwarded that one port for that
Xbox. Since I can't use the same ports for the second Xbox, what ports do I forward? I have open NAT on both Xboxes but my husband still has a hard time connecting to multiplayer games on his Xbox.

I keep getting disconnected from party chat on my first Xbox without warning. I've already tried power cycling my Xbox, power cycling my modem and router, clearing the MAC address, and everything else I can think of. Is it a router problem or an Xbox problem?

Sorry if this is vague, I'll clarify if I need to.

:)