In order of my google search’s results.

https://thehill.com/policy/defense/4043221-ukraine-kakhovka-dam-collapse-theories/

https://www.politico.eu/article/ukraine-says-russia-admits-blowing-up-nova-kakhovka-dam-call-intercepted/

https://www.nytimes.com/interactive/2023/06/16/world/europe/ukraine-kakhovka-dam-collapse.html

https://www.bbc.com/news/world-europe-65818705

Most of these articles admit that it is kind of impossible to know for sure in the middle of a warzone. It’s as likely that it collapsed due to lack of proper maintenance in the middle of a war.

What’s your source?