Putin took Crimea under Obama, trying to take rest of Ukraine under Biden, did nothing under Trump. These facts are incompatible with notion that Putin hacked 2016 election for Trump. Putin was restrained by Trump’s strength & unpredictability, is unrestrained by Biden.
Every school kid knows that bullies are attracted to weakness but leave the biggest boys alone. But by the time you complete graduate school in political science, that obvious truth is forgotten.