Having a Pro1X since August on Salt Network in Switzerland and observed a clear weaker cellular connectivity comparing to other phones in my company with the same provider. The mentioned waiting time before call-start or even non-availibility for incoming calls is a regular fact.
After now a week of business-traveling with roaming in Italy, I plan to change my phone. Comparing to my business-partner with a Z-Flip I was often lost with connectivity, or with a rate below 1Mbit with a Samsung on full speed beside me. My physical-keyboard-phone is worthless, when I live on the moon with it.