Why would we judge heterosexual masculinity by insecurity? Yes there are deep ties there, but those deep ties are more based on a precarious position of a neutral trait being held up as an ideal and imbued with societal power. The insecurity is a byproduct of patriarchy favoring it and thus incentivizing those who do not embody it faking it. I would instead say that folks like Nick Offerman who both embody it and reject its dominance are the ones who hold it most. Someone like Steven Crowder for example who clearly hates the cigars he smokes and the whiskey he drinks and just reeks of a bad performance of heterosexual masculinity clearly lacks any authentic expression of gender and orientation.
Trump is clearly a straight man and a masculine one for his culture. I believe the performance he gives, but his insecurities seem to be of value and of strength, especially as he ages and declines. That insecurity is not inherent to straight men, but rather rampant among them