[cirgue]

In addition to other commenters providing sources for this assertion, there is also the fact that Russia's current strategic doctrine is to disrupt and delegitimize governing institutions of rival states, and Russia considers pretty much everyone a rival. Moscow's operating assumption is that the current international stage is chaotic, resource-poor, and intensely competitive, such that sustainable cooperation between between major powers is not only unlikely, but also that attempts at development or stabilization of an international cooperative order would be potentially catastrophic.

This is to say: Russia has a powerful incentive to do everything up to and including manipulating foreign elections, but in the eyes of Putin it is sufficient to be seen to be manipulating foreign elections. Arguably, this has a greater effect on the capacities of his adversaries, because democratic systems don't really work without a general consensus that elections are legitimate. Russia does not want an alliance with a strong US and EU, they want no alliance with a greatly weakened US and EU.