Here's my take on testing[0].
I write Quality software. It's a matter of personal satisfaction. Many folks can't really tell the difference between relatively good software, and very high Quality software, but the cost difference can be quite large. We don't get rich, writing top-shelf software.
The issue is, in my opinion, that we don't even produce much "relatively good" software, these days.
I won't get into it. It doesn't win me any friends. I was fortunate, to find a company that shared my values. Many of their processes would absolutely horrify a majority of folks on this site, and it was, quite frankly, often maddening.
But you can't argue with results. They produced extremely expensive kit, for over 100 years, and they are regularly used on the ISS.
[0] https://littlegreenviper.com/miscellany/testing-harness-vs-u...