I believe the truth will lie in the middle - Boris didn't 'tank' or 'sabotage', but there is wider interest from the US/EU/UK in the war continuing. US's and Victoria Nuland's involvement in Ukraine in Maidan is enough for me to question such.
Russia has targeted infrastructure obviously, as does any side in a war. Yes, Ukraine should be left alone to have its say on the EU - sadly that's not the case and never will be.
Nato question is a much bigger one that I haven't formed a clear opinion on. Nato expansion is a thing. Ukraine joining Nato wouldn't be a step toward peace.