
Obviously, yoga is a movement practice and thus, one could write a very practical book about the muscles, ligaments, and tendons, how to foam roll and massage to enhance yoga, how yoga has scientifically proven health benefits, etc.
Similarly for mindfulness, you look at Joseph Goldstein's book Insight Meditation, and it's mostly a combination of stories from his life as a Buddhist in Asia, alongside his learnings from Buddhist teachings. Nowhere does he claim it's scientific nor does he attempt to use pseudoscience. He stays in his lane and the book is a great one.
So, friend, I'd say don't besmirch two very ancient and healthy habits which have aided millions of people, especially when you give zero pieces of evidence while seemingly not actually knowing those fields.
"Confession of a Buddhist Atheist" by Stephon Batchelor. Useful to me for understanding the cultural context of Buddhism.
Insight Meditation by Joseph Goldstein. I just find Goldstein's style the easiest to comprehend in a field that often comes across as frustratingly esoteric
Wherever You Go There You Are by Jon Kabat-Zinn. I thought this book is interesting because it draws parallels to Western authors, particularly Thoreau.
Sam Harris's "Waking Up" app may also be worth a listen. Besides the actual mindfulness practice, there are a lot of discussions on theory and he has conversations with a variety of people that come to the topic from different perspectives.