I have exactly the opposite problem: tons of legitimate email is getting flagged as Spam by GMail. It's now happening regularly with emails from people in my contacts with whom I regularly exchange messages . Mind-boggling. I know spam filtering is a hard problem, but these are just obvious misses.
20% of what is in my "Spam" folder today is what I'd call "spam" in the classical 90s/2000s-internet sense. Obvious trash/scam stuff, usually sex-related.
Most of the rest of my "Spam" looks like what Gmail usually just labels Promotions. It's mail from legitimate organizations that I did indeed give my email address to and have a reasonable expectation of getting semi-regular email from, even if it's just trying to sell me more stuff. The Promotions auto-labeling works (worked) just fine for managing that stuff.
I figured enough users are clicking the "Spam" button on enough "legit promotional" email from real organizations that they did agree to receive email from, that Gmail just started classifying it all as spam, and now doesn't/can't distinguish between "classic" spam and "annoying emails I can't be bothered to unsubscribe from". Sort of a tragedy of the commons of crowd-sourced spam filtering. But maybe there's a better explanation.