Alerts to my Iphone are not consistent

My Ring system was installed 12 days ago 10/5/2025. Everything seemed to be working fine, but then shortly after I was not getting alerts to my Iphone. Today I updated the phone to IOS18. I tested the alerts by going in and out of the home. It worked fine, then an hour later the alerts quit being sent to my phone. I spent a good part of the day yesterday chatting with Ring (twice). The last person said it probably was my phone and gave me Apple support #. This morning with Apple support the tech checked my phone and found the only thing she suggested would be an update from 14 to 18. Well, I did that and still the alerts to my phone are inconsistent. I have checked the health of the devices and only one is getting a "Poor" signal, the rest are getting a "strong" signal. HELP!