In short, it is entirely possible that Trump is correct. The political discourse can't keep shutting down in emergencies, there are too many emergencies these days for that to be an option. People have to talk calmly about what they think is happening.
Exercises and bases in all Eastern Europe intensified under Trump.
He likes to talk nicely about people that he's going to strike. Like he always says he likes Xi, but then start a trade war anyway.
He blocked NS2, Biden opened it in his first week in office.
If Trump was so weak toward Putin, Putin would have invaded with Trump in the White House...but Putin invaded with Biden there(and previously woth Obama). Makes you think, doesn't it?
He has been closely in bed with the sections of media that have pushed the narrative, generally celebrated paranoia towards experts, and consistently pushed the idea that you can't trust the government. If you lose control of the bolder you helped push onto the slope, it doesn't mean that you don't have responsibility in pushing it to begin with.
He was also instrumental in pushing early treatments that didn't pan out as hoped. These often became the subject of conspiracy theories about a whole slew of medical professionals avoiding real treatment, and the pandemic being some authoritarian plot. Trump was there sowing doubt in medical professionals. He may have encouraged vaccination itself, but his actions on the whole produced distrust so that there is a pronounced deficit of vaccination in his electorate.