I was having problems with getting wifi calling to work with my and my wife's phones (both iPhone 13s) on my archer c4000, so I followed all the instructions on https://www.tp-link.com/us/support/faq/1259/ 

I set it the router as instructed on this support page for the IP I reserved for my phone (updates firmware, disabled SIP ALG, reserved IP for my phone, enabled port forwarding for 500 and 4500.). I also tried to enable the port trigger entries for 500 and 4500 as suggested in the optional step 5, but I am not sure I did it correctly.
 

and, this worked! So now wifi calling works (most of the time) on MY phone.

However, the problem is, my wife needs wifi calling too. And everything is set in the router to go to the IP I reserved for my phone.

is there anything we can do? Would a different router help?  We have been very happy with the router for several years other than this issue.