My husband and I can’t play together

What platform are you guys on? My girlfriend and I play bf6 together on the same network (both hardwired), but I'm on Xbox and she's on PS5. We've had AT&T fiber Internet for about a year and a half and when we first got it, I noticed the "NAT" status in my Xbox's network settings had become "strict" but when we had Xfinity cable Internet the NAT status was always listed as "Open".  I know this can affect matchmaking so I had to ultimately go into the settings for my fiber gateway, turn off the built in wifi, set up the "ip passthrough" mode in the gateway's settings, and hooked up an external regular wifi router so that upnp would work correctly (because my Xbox's network settings were showing that upnp was also not working when I was using only the AT&T gateway). Then my Xbox's NAT status went back to "open".  Not sure if you're using fiber Internet or if your network NAT is restrictive or how to check that on anything aside from Xbox or PlayStation though.