It doesn't matter if you are new or not. Your experience is unique and I would be very interested if Kevzara works for you.
I take a multivitamin but that dates back to when I was on Prednisone. Kevzara isn't known to deplete vitamins in the way Prednisone does.

I was able to taper off Prednisone about 4 years ago after Actemra was started. Kevzara should work in the same way that Actemra works. Neither Actemra or Kevzara work as fast as Prednisone works. It sometimes takes a few injections before you start to notice less pain.

How is your pain? What type of spinal fusion did you have? I was supposed to have a lumbar spinal fusion many years ago. At the time, the spine surgeon said the surgery would be very risky because I was taking so much Prednisone and I wasn't able to stop prednisone. Pain was going to be the "deciding factor" for going ahead with a lumbar fusion.

Now that I'm off Prednisone, the spine surgeon says I can do surgery whenever I'm ready. I honestly think Actemra is keeping the pain and inflammation in my lumbar spine under control. I don't want to do the lumbar fusion. However, I still have severe spinal stenosis.

The following link has some information that compares Kevzara to Prednisone.
https://www.drugs.com/compare/kevzara-vs-prednisone#:~:text=Kevzara%20has%20an%20average%20rating,17%25%20reported%20a%20negative%20effect.