The truth is simply the facts. Fact is that people entered the Capitol without permission. Some were armed and did take the risk to kill someone in this raid. True is also, that Trump pushed a narrative, that probably the elections will be rigged. There was never any evidence pointing in unusual amount of anomalies in this elections.

Those are facts one can verify or falsify. Therefore they are objective. Because different people can verify this event and what happened there independently and will find the same truth. But evaluating these facts is not part of truth finding. This is then a second step, where one takes a stance. To say it is a good or a bad action is a position, one can choose, depending on your liking. Fact is only what happened there. It is a fact, that members of the proud boys were there some of the leading figures. It is also a fact, that water freezes at 0°C and that it boils at 100°C, when the air pressure is around 1 bar. These are examples of truth. And anyone willing to do so can question such a fact and take it to the test. And when it is true, they will find the same result.