The previous - and very possibly future - President openly espoused Putin-friendly propaganda and threatened to leave NATO. European dependence on American power worked for many decades, but may leave them in a very tough situation now.
If Trump really is Putin-friendly, then Putin made a massive mistake by delaying his major military actions in Ukraine until Biden was in office.
I have no real proof of this but I suspect if Putin did delay his actions until Trump was out of office, it was because Trump was such a wild card that Putin might think that he could try to nuke the Kremlin if he didn't like what was going on in ukraine.
Disease killed more people on the frontlines in WW1 then weapons did, and it is the foolish military planner who doesn't try to avoid it (the Russian lines are currently dealing with an outbreak of Cholera in parts, which is another problem partly as a result of training quality - effective military's drill field hygiene practices because it's a direct contributor to combat effectiveness).
EDIT: i.e. when there's a novel respiratory virus about, nothing will destroy your military faster then massing for an invasion in one place.