My wife tracked her stuff daily.
When I said “She was never regular” it drifted between 30 and 37 days before kids, to 32 after the second one.
Note, that was even before we had intercourse. NFP is pretty good for things like that.
The Doc mentioned that many women are NOT regular, hence the tracking.
So, in the words of my generation, “Lighten up!”
Did you not read the article? The most concerned women are those who have had regular cycles, or who have been post-menopause for years and their periods came back (something that has happened to some women diagnosed with actual Covid to be fair) — or women who are on birth control.