Thank you! The article that you sent me showed me how to adjust time zones on individual events. After reading that and looking at my calendar, I realized that the only events that were showing the time zone were ones created by my wife on her iPhone. Those on iPhone and on the MacBook weren't showing the time zone. Why?
Because, it's Apple!
She was creating events in Eastern time (New York) while my devices are Eastern time (Detroit). Last I checked, those are, in fact, the same time and have been for quite a while. Alas, because Apple has multiple cities in the same timezone and isn't smart enough to figure out that they are the same, it was messing up my calendar.
So, your response didn't directly solve my problem, but the article helped me to explore a bit deeper. Many thanks.