Seems like a great one to me:
New Marquette Law School national survey finds Democrats expand lead on congressional ballots; Trump approval declines
The survey was conducted Sept. 2-9, 2026, interviewing 1,023 adults nationwide, with a margin of error of +/-3.3 percentage points. For registered voters, the sample size is 864, with a margin of error of +/-3.6. For likely voters, the sample size is 581, with a margin of error of +/-4.3 percentage points.