Hi, i can't help for the office thing but I had the same trouble for the phone app. It looks stupid but there is no default phone app selected so it just don't know what to do with calls. Go in apps settings, select default apps and phone is probably empty and it shouldn't be, which was the case for me.
It is partly a hardware issue that should be flawlessly corrected with proper software, as I've described. My repeated key issues started about 9 months ago. Same thing with my Photon Q. I'm surprised the backspace key didn't break off and fall right out of the phone.
That's very interesting that it's happening on LineageOS as well. But I'd have to guess that the way keyboard input is processed on LineageOS was just "borrowed" from Android.
I'm an old-school microcontroller coder, and I have an example of this happening in early 80's tech. I have an old Radio Shack programmable