I bought my wife an X Charge almost a year ago because her previous phone (X Power) always had poor signal around parts of our house, and calls were always breaking up and hard to hear. The X Charge was more-or-less an upgrade of that phone with WiFi Calling.
I really hoped the WiFi calling would help, but she constantly complained of calls dropping or the other person not able to hear her. We do have a baby that sometimes touches her phone so I always said to check if WiFi was turned off, etc, or something else like that because it didn't make sense that she'd still be having trouble even with the WiFi Calling feature.
Sure enough, I needed to use her phone recently, and the other party said they could barely hear me, the call was breaking up, and I looked at her phone and saw it showed 2-3 bars (!!) and perfect WiFi coverage. My phone is a Moto G5 plus and it has decent enough coverage upstairs in our home (2-3 bars of service), but downstairs the calls usually won't work because it drops dramatically in the basement. Her phone makes calls downstairs just fine, and I can see it is because of WiFi calling, but it seems that the quality of her calls is just bad, upstairs or downstairs. I'm wondering- could it be that it is poorly handing off calls between wifi and cellular?
To be honest, I tried turning off WiFi completely and calls sometimes still do it on her phone, even upstairs with good reception. Meanwhile my Moto seems to either work or not, depending on where I am in the house, but when it does it works fine.

I'm wondering now- do the LG X series from Cricket just have poor call quality? Would a different WiFi calling capable phone do better? She doesn't like Apple phones so that isn't really an option, but I'm open to anything that would work better for her.