If you want to call what happened on January 6 a "coup attempt", (with ensuing "counter coup",) you _can_, but then it's the lamest coup ever.
When an event would be the most outlying member of its category, it's worth asking if it actually belongs.
https://slate.com/news-and-politics/2021/01/trump-coup-violence-capitol-national-guard.html
You might as well say "taxation is theft".
You're technically correct, but so far away from common usage that it's not worth bothering.