But yes, there is a large and qualitative difference between a riot with property damage and attempting a full on coup d'etat. The latter is a crime against the very heart of society.
To be clear, if the Trump supporters had stood outside Capitol and protested, even violently, it would not have been such a momentuous thing. Crossing the Rubicon indeed.
Then the President told the crowd at the rally to march with him to the capitol to pressure Congress into overturning the election results.
People then marched down to the capitol, broke into it, killed a police officer, and forced congress to evacuate. When asked why, rioters stated they were trying to prevent Congress from certifying the results.
It was a failed attempt at a coup, and a very bad attempt at a coup. It was still an attempt though.
Aside from all those frightening cases, it seems clear that there was a broadly shared goal was to "stop the steal" by preventing Congress from making progress in the peaceful transfer of power to the Biden administration. Maybe most of them had few concrete ideas how they'd accomplish that aim once inside the building, but they nonetheless were aiming to overturn an election and block Biden from becoming President - and if successful that absolutely is a coup.