Are you actually arguing semantics now ?
"German prosecutors blame Ukrainian government" vs "German prosecutors try to establish connection between the commando and mid-level figures in Ukrainian military" is a huge, meaningful difference and not just 'semantics'.
Semantics really, we all know it was western backed and likely orchestrated by MI-6/CIA types. Germany can pretend it's some rando-commando Ukrainian but you really have to suspend your intellect to believe that.
Why would the MI6 or the CIA take such a huge risk, though? At the time NS was blown up, it had already been inoperative for months (because Russia itself had shut it down). All that blowing it up accomplished was taking a scenario off the table in which Russia promises Germany to resume gas supplies via NS, the German side trusts them in spite of Russia just having proven its untrustworthiness, and then Germany being willing to completely turn on all its European and NATO allies. A very far-fetched scenario.
The risks, on the other hand, were dramatic. If anything during the operation goes wrong and the "true" instigators are found out quickly after the fact, you have a veritable diplomatic crisis and just drove a far bigger wedge between the allies than Russia ever could have. For Western state actors, the calculus just made no sense at that point in time. Such a gungho move only made sense from the perspective of true hardliners in Ukraine or perhaps Poland.