Is there a connection of biologics to brainfog?

I (37m) was formally diagnosed about 2 years ago. I've been on Simlandi since. However I've probably been suffering from AS for most of my adult life. In the 2 years since I've been diagnosed I'm feeling a lot better, greatly reduced pain. However slowly over the last 2 years I've noticed my performance at work has been slipping. Even if I'm motivated and trying hard, it doesn't come as easy as it used to. I'm in software working at the architect level.

Anybody else experience thing?