Yeah as I said, I don't believe much coming from these investigations unless all evidence is open sourced so that people can independently go through it and decide for themselves. But let's have some fun and play around with this theory. It could make sense for Ukraine to sabotage the pipelines for two reasons: 1. Less natural gas sales to Europe means less war capital for Russia (maybe a bit naive outcome?) and 2. to turn the EU even more against Russia (as long as Russia is blamed) which could increase the amount of war material gifted to Ukraine. That said, personally, I think this theory is too naive and simple.