Some very intriguing observations, Tink. I hope you are indeed one of the people who, if gets it, few or no sx...
I have had similar wonderings about myself, because I had a strange sort of something for 6 - 8 wks in March and April 2020...very mild, morning sniffles/sore throat, mild cough, etc. But there were very few tests available then, and I could not convince our health dept. to spend one of their precious tests on me.
So I got their best guidelines on how to quarantine, and did that anyway...LONG time, because I kept it up for a while even after all symptoms disappeared.
But now, I seem to get exposed, and not get sick; as when I was with my neighbor -- after talking with 911, I ran back to Donna mask in hand, I forgot to replace it! ...carried out 911 instructions with her, sat with her until ER arrived...all no mask, no protection!
*. *. *
Strangely, I have never had painful migraines, but beginning in 2010, I do occasionally get something ocular that I just recently discovered from the Internet, is probably ocular migraines! ...and after a long absence, recently now say over the past 18 months, I do get one maybe every 6 or 8 weeks...if this COVID were not so devastating, I would consider it extremely interesting.