Kevin Hall also did a fascinating study on ultra-processed vs less processed foods which found that people ate more and gained more weight on ultra-processed foods even when the two diets were identical in macronutrient composition! I would guess that the main reason dramatically different diets show similar levels of effectiveness is that all of them involve drastically limiting intake of ultra-processed foods.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7946062/