We might not know whodunnit for a while, if ever
For those who understand that the US empire is in its death throes, it is already known what state agency was responsible.
The taking out of the Nordstream pipelines only extends the US empire's dominion over Europe temporarily, as the coming Winter months and far worse EU economic collapse will cause the European people to break their vassal status to the US empire.
The important thing is that WW3 just started and if you wanted anything from Germany you’d better get it now
The kinetic phase of WWIII has already started earlier this year when Russia decided to stop US imperial / NATO expansion into Ukraine. The potential of nukes won't start flying unless US imperial vassal and Russia-hating NATO nations like Poland decide to go rogue and launch attacks into the Russian Motherland, thereby, opening the possibility of nuclear catastrophe.
On the Asian front, kinetic action will begin once the US empire begins supplying offensive capable weapons to the Republic of China (ROC) / Taiwan. Since the Power Okole's senile old fool in the White House revealed the US empire's intentions to militarily intervene on behalf of the ROC, China will not wait for the military integration of the ROC's forces into the US imperial military and do a Ukraine 2.0, but immediately use all means at its disposal to reunify their renegade province preemptively.
If the US empire decides to fight China, then pray that only domestic Balkanization and economic collapse occurs, since the only alternative to those scenarios at that point is nuclear annihilation.