I suspect that if you have a situation where people's "situation" (to use the word twice) doesn't change much from year to year but they feel they're slipping b

I suspect that if you have a situation where people's "situation" (to use the word twice) doesn't change much from year to year but they feel they're slipping behind/worse (e.g, inflation but everything else is basically the same) - you'll find a decline in the birthrate. If you have a situation where suddenly your life improves noticeably, birthrates will rise - even if the first group is always better off than the second. It's relative. So WFH may have contributed to a birth rate rise simply because people felt more secure and more in control (or better) than they did before.