Who I have the same questioned this topic

Recently my Iphone 13 has been going into SOS mode  at my home only.  I have very poor coverage in this area and about 4 months ago  I got a Verizon network extender that helped tremendously.  I was on phone with Verizon for 3 + hours trying all different options and nothing worked.  I went into a Verizon store and they gave me a new Sim card and  updated the lasted IOS and said I would be fine.  Was at home for not more than 2 minutes and back in SOS.  The phone works fine outside the home.

I turned off the extender and plugged back in and my phone went back to strong signal and worked for a couple days and then same thing happened.  Turned off extender and restarted and again back working for a couple days.

Outside of my house I have no issues with the phone

If I turn off WiFi connection when in SOS mode i still stay in SOS mode.  

I am thinking maybe the extender is bad?

Would appreciate any feedback or suggestions.