“The number of illegal immigrants in the country has roughly doubled under President Biden. The United States had some 10.2 million illegal immigrants in 2020, and another 10 million have entered during Biden’s presidency. If the 20 million illegal immigrants were all in one state, it would be tied with New York for the fourth most populated state.”

First, it's not ten million. Total encounters by Border Patrol for 1.2 million in 2021, 2.2 million in 2022, 2.0 million in 2023, and 1.3 million YTD (note that the USBP year runs Sept-Oct, not calendar year, so the 2021 is just for the portion of the year after Biden took office). About 6.7 million.

Next, about half of the 6.7 million that "have entered" during Biden's presidency were immediately ejected under Title 42. They didn't spend any time running around the country. Again, for most of the Biden administration (all of 2021 and 2022, and a good chunk of 2023), the Title 42 expulsion policy was still in effect. Most of the people who were encountered during that time were immediately expelled from the country.

Of the 3 million who came in under Title 8, about 40% of those also immediately left the country. About a third were eligible for expedited removal, another few percent had outstanding removal orders, and another few percent left on their own rather than stay after they had gotten caught.

You have maybe about 1.8 million (roughly) that "entered" the country illegally but weren't immediately sent home. Against that you have maybe 500-600K that have either been deported or legalized over the last 3.5 years.

So, no. You don't have 10 million new illegal migrants hanging around the country. You might have seen the illegal population increase by a little more than a million people during the President's term. Nowhere close to ten million. Because, again, the entire population of the entire country has only increased by four million people over that time frame.

These folks are trying to mislead you by pointing to "entries" and creating the false impression that they nearly all stayed around, when in fact about 80% of them left almost immediately. Don't fall for it, LM!

cbp.gov - Title and title statistics
cbp.gov - Custody and transfer statistics