Pattern predicts PEM crashes

Ever since I got COVID three years ago, I experience periodic "crashes." These start with a distinct feeling of exhaustion radiating from my chest throughout my body. It kind of feels like the flu coming on without the muscle aches or fever. I am then wiped out for 3-4 days feeling exhausted. I often have chest pain that kind of feels like I've been lifting weights and I get a congestion-like cough but no real congestion. I've struggled to figure out what is going on and had every kind of medical work up you can imagine (heart, lungs, blood, etc.). About a year ago I starting wearing a Garmin watch and logging when I had these crashes. I was hoping it might reveal something but I could never make sense of the data - until now. On a lark, I decided to download the Garmin data and put it in AI. It found that 3-4 days before these crashes, I have a day where my average heart rate is elevated and my average stress level is high. One day it was a family BBQ. Another was a day that I was travelling. I didn't feel anything out of the ordinary those days but sure enough, 3 to 4 days later I crashed. So I'm wondering if anyone else has seen this pattern? And if so, what steps did you take?