What is the choice of firmware for Blu Vivo Air LTE?

Question

Android

My wife has a beautiful Blu Vivo Air LTE phone with not perfect firmware. Complains very often. Something needs to be changed. As a last resort, the phone :)
It seems like cyanogenmod is good at what it does, but how to make sure that their assembly will fit the phone? The list of supported phone models does not even include blu\fly.
What are the options?
PS There is no experience in changing firmware on phones