Another Nexus 5X user here and also dissatisfied. A while back, my phone stopped being able to answer calls. It rings, but no UI dialog appears on screen to let me answer. This is a known issue that I've seen on support forums, but nothing suggested there has fixed it. I've spoken with Fi support on multiple occasions and they've exhausted all options and now want me to wipe my phone hoping that will fix the problem.

I'm amazed at how poor the Android experience has been after years on iPhone. I'm still more amazed that Android is as popular as it is despite all this.