I'd argue, yes. By analogy, was the Storming of the Bastille an attempt to overthrow the French monarchy?... Fuck, yes! It's impossible to argue that an attempt to storm the seat of government was not an attempted coup.
The problem was that January 6 was inept and idiotic. But that just means it was an incompetent coup attempt. What if they had found and killed Pelosi? Or Pence?
They actually came much closer to pulling it off than people realize.
Their goal was to delay the proceedings to the point they weren't complete and put more pressure on Pence to do what Trump wanted. (Some also thought - sill think, even - that the way the law is written means that if it wasn't completed by midnight it didn't count.)
Anything to put enough confusion about the results in play that it could get kicked to the house or the Supreme Court would have to step in.
They did a fairly good job of that. They delayed it for hours, they put people in fear of their lives, which could have swayed votes enough to get things called off.
Pence was encouraged to leave but didn't, which means the delay didn't last days, which it might have otherwise.
So yes, it was a last ditch crazy bank shot approach because earlier pressure hadn't gotten him where he needed, but even under those terms it accomplished a lot of what it set out to do.