Iphone Xs max, Network issues... Hardware or Software?

Hey there so the wife and I have had our Xs Max's since last September and had little to no issue until here lately and we've had some very odd and peculiar things our iPhones have been doing off and on, my wife's more than mine, keep in mind there both the same exact model except color variation I have "black" she has a "rose gold" both are 512 GB models, Both are operating on the Sprint Network which in my area blows the majority of the competition out of the water... Anyways about 12-13 days ago my wife's phone would NOT dial any numbers except mine, you would dial the number it sometimes would ring one time and then you'd hear double beeps like a "call failed" also her iwatch wasn't working while her phone was powered on only when it was off, I tried soft resets, I tried resetting the network settings, I tried updating the PRL lists, I removed the sim card I even wiped the entire device clean and still the same issue, of course sprint and the advance techs were oblivious, as was I, keep in mind my phone worked perfectly this entire time no issues what so ever sitting directly beside her... So jump forward two days her phone all of a sudden is working, just bam, later that day mine started having the same issue while trying to dial out... After 24 hours it stopped too, it was just blew my mind as what could have been causing the issue... The software was all up to date like always, the network "seemed" to be working well the customer service reps said it looked fine, I checked the "GSM" side of things on the lte spectrum and the download speeds were great and uploads looked perfect... I was just wondering if anyone else has experienced anything like this... Thanks