Opening NAT on airport extreme for xbox?

PLEASE HELP, i have done everything. i have turned on upnp on my modem, as well as opening ports, so now i believe the reason why i have a strict nat would have to be my router. i have tried opening the ports, but to no avail 😡. is there somthing i am not doing? i do not have a costum ip (forgot what its called) and i am new to this stuff. i dont want to have to pay geek squad 150 bucks, nor do i want to buy a new router. i am stumped

please help + bump🙁 another bump, my mac- smart uncle is here. still seaking an answer