Sheesh, a complicated thread has gotten even more complicated. Now you're talking about presidential immunity as well as the Colorado case. They are intertwined in a sense, but both are going to go up to SCOTUS and I'm glad - this needs to be settled once and for all.
Starting with the immunity case, more of an uncharted territory thing. Look, there's never been a former POTUS in the country's history that has been indicted or prosecuted for anything that happened in the presidency. As someone above has said, Nixon did get that pardon, but it wasn't because Ford thought Nixon didn't have immunity - he may have, he may not have, Ford didn't want to "go there". But there we are.
What's SCOTUS gonna do? You never know, but I don't see how Trump could be convicted of insurrection. He was tried in the Senate and acquitted - if that had never happened:
Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.
That implies to me that indicting Trump for insurrection is double jeopardy. I think SCOTUS will narrow down the immunity question as specifically as possible to avoid an "anything goes, he's untouchable" ruling to a "you can indict him for anything, Let's dig up Thomas Jefferson now" ruling. So I think the court will decide Trump has immunity for Jan 6 in the end.
Now that other case, Colorado and Maine, there's several ways that could go. Hmmm, Most likely, a reversal for sure, due process would actually be a harder path for Trump because the court would have to say that the disqualification procedure was wrong and how, and that would tell them exactly how to disqualify him (and Biden and anyone else). SCOTUS could overturn it without comment, and doing that would beget even MORE lawsuits
Guess they could squint their eyes and claim that the president is NOT an officer of the US, so no section 3, very unlikely. A little more probable is to rule that disqualification under section 3 is an exclusive federal issue, they just can't. And there's no way SCOTUS will say Trump wasn't an officer of the US at the time, nor will they delay a ruling. They could say these two states are full of it, they might have thought it was an insurrection, but it wasn't but the easiest way to do this is to define "insurrection" and then explain why Jan 6 wasn't. That's the most likely outcome, SCOTUS tries to go out of its way to resolve cases on non-constitutional grounds and here it is! Don't see how they can duck that on the immunity case, though .....