A majority of U.S. Senators voted "guilty" when Trump was impeached for "incitement of insurrection". This was not enough to convict, but there was substantial evidence presented. The J6 committee found even more evidence of insurrection, and the civil trials will allow all parties opportunity to present the evidence in court.

I mean, sure - but so what? The Senate impeachment trial wasn't a judicial proceeding, and they didn't render a decision of guilt; nor were the J6 committee investigations. You would never be able to walk into court on a civil proceeding against Trump and tell the judge, "Look, a majority of the Senate voted that he incited an insurrection, so I'd like you to accept that point as proven." The court would - correctly - insist that Trump should have an opportunity to mount a defense. To cross examine all witnesses, to present any defense witnesses he wanted, to make arguments on the legal points relating to the definition of "insurrection" within the meaning of the 14th Amendment, etc.

I have no doubt Trump planned and supported the January 6th United States Capitol attack, in an effort to stop the vote certification and move the election into the House.

Fair enough - personally, I doubt it very, very much. I mean, I think he was delighted that people were so enthused about his Presidency that they were willing to commit violent crimes and throw their lives away for him - what more could a narcissist want? But I think it's pretty likely that he had no idea that was going to happen, and had no idea what to do once it started happening. Nothing was in place to take advantage of the chaos - no one was prepared to use the chaos to Trump's advantage. Which is why, even though you had near-maximal disruption to the proceedings, they just went ahead and voted once things were secured.