Few doctors are familiar with lupus or any other AI disease. I had a team of doctors and there were as many as 3 rheumies and 7 other docs working together on my case. Even so, each case is different in presentation, how the disease progresses, and how it responds to treatment. One of the docs was a well known clinical researcher and he was the guru of the team.
I had specialists dealing with each aspect of my illnesses (lupus, polymyositis and scleroderma) but working together as though in a large clinic. You have to be your own advocate and find doctors, if you can, who have experience treating lupus.
There is no such thing as an average flare. Each of us is different.
Kidney function is measured by eGFR which measures how efficiently the kidneys filter your blood.