I was aware around the time the census was being taken that there were Republican efforts to distort the outcome; click here for an article at msnbc.com, The ReidOut Blog, by Ja'han Jones, titled "The Jan. 6 insurrection failed. But this Trump plot to undermine democracy didn't."
The U.S. census is taken every 10 years. It's important that it be accurate, because it determines how representation in the House will be redistributed and how services will be provided for marginalized, vulnreable populations; click here for an article at Vox by Alvin Chang, titled "How Republicans are undermining the 2020 census, explained with a cartoon."
Those populations are routinely undercounted:
The undercount happens because those people are harder to find. They tend to be more transient, less trustful of government, and less tied to communities.
So the count is usually distorted to some degree despite best efforts; in 2020, the Trump administration and Republican states made a concerted effort to deliberately undercount these populations so they would not be allowed access to government funding.
The Trump administration also tried repeatedly, but failed, to have a new question added to the census: "Are you an American citizen?"
In field testing, this question was very effective in discouraging non-citizens from responding to the census for fear the government would use the document to find and deport them, which could lead to a massive undercounting of non-citizens and resulting in inadequate government funding for programs intended to help marginalized people.