Several Proud Boys have been charged and convicted of Insurrection now, and several of them have explicitly said they felt they were acting on Trump's orders. I don't feel there's too many dots in line to connect them together enough to disqualify Trump now.
That's a problematic line of reasoning. In general, one's belief that he has been deputized by some authority and is acting properly under that authority doesn't automatically attach liability to that authority. Nor is the agent completely absolved—even if the agent is an authentic deputy. That the President orders you to attack someone does not remove your responsibility to act in conscientious accordance with the law.
Conversely it doesn't matter whether anyone believes or obeys an authority's orders. If the President knowingly orders an act of insurrection, he is liable for that attempt whether or not it succeeded. Criminal law does not generally require a criminal effort to succeed in order for liability to attach.
To repeat the hackneyed phrase, it's going to come down to what did the President know and when did he know it. If Trump truly believed he was encouraging people to save democracy by protesting the certification of a stolen election, he might escape liability (but probably not, since the President has many tools available to him other than the deputization of an armed mob). But Trump's other statements and the observations of others cast doubt on the veracity of any such belief.
Trump's best defense is that he never ordered anyone to do anything illegal or as part of a seditious conspiracy. He can try to say he meant to organize and lead a peaceful protest outside the Capitol and that any who took his statements as authorization for or instructions to carry out an violent, armed intervention were mistaken. That certain people got the wrong impression isn't his fault. Even in the hands of a skilled prosecutor, what any number of people understood Trump to have meant doesn't provide evidence for his actual mental state.
I guess, good luck with that kind of defense. Trump knew the audience for his speech was armed. He took affirmative steps as President to ensure that they could remain armed. He invited them to march to the Capitol and promised that he would join them. Knowing what we know about Donald Trump, it's not out of the question to suppose that he planned to march at the head of a vast throng of his armed supporters, storming into the Capitol and demanding that the Vice President reject the "fraudulent" votes from states that voted against him, and instead accept his alternate electors, thereby saving democracy from the Deep State. He seems to have been prevented from doing some such thing only by the Secret Service. And that may help him legally since actions are harder to explain away than words.
Of course the mistake is to believe Trump took or contemplated any of these actions out of anything but narcissism. Remember he's really only in this for the ratings. He likely wanted visuals on the 6 o'clock news (Is that even a thing anymore?) of him appearing as the personal champion of truth, justice, and the American way. It's not about those ideals. It's about Trump being associated personally with defense of those ideals, and thereby reinforcing his cult of personality. The notion that his actions might be considered some kind of insurrection (justified or not) probably never entered his thinking.
Where Trump might actually get into trouble is in his promise to pardon those convicted from the Jan. 6 insurrection. Regardless of whether it can be established that he ordered them to do what they did, a promise of pardon could be seen to give aid and comfort to those actors. It will be hard to argue that he approves of their behavior enough to pardon them, but not enough to be identified with their criminal conspiracy.