The fact-finding role of the trial courts is to determine the overall factual setting of the events. Appellate courts normally do not intervene with those findings of fact (but see the SCOTUS decision in the praying football coach for a counter-example).
But the next step in a trial court’s analysis is always to apply the law to those facts. To the extent that step requires an interpretation of the law, it can be subject to appellate review. The trial judge has to get the law right, in their analysis of the case, when they apply the law to the facts as found.
And that’s where the legal issue comes up here. The Colorado trial court made findings of fact about what Trump did in the lead-up to January 6, and what he did on January 6. My guess is that the Supreme Court is highly unlikely to interfere with those factual findings of the narrative of what Trump did.
But, given those findings of fact, the real issue is a legal one: did Trump’s actions amount to an « insurrection », as that term is used in the 14th Amendment? « Insurrection » is not defined and the Supreme Court will have to give some ruling as to what « insurrection » means, as a matter of constitutional law. Then they will have to make the determination: given the facts as found by the trial judge, did Trump’s actions qualify as an « insurrection », as that term is used in the 14th Amendment, triggering his disqualification?
TLDR: the trial court’s finding that Trump engaged in « insurrection » contains both factual and legal findings. Appellate courts can review the legal findings that are contained in a trial court’s ruling.