It's exceptionally unlikely that the number of illegal immigrants that could be attributed to the current Administration would be anywhere close to 10 million. That's probably off by about an order of magnitude or more. The total illegal population isn't much higher than it was at any point in the Trump Administration, certainly not as much as a million people:

“Matthews: Illegal immigrants double under Biden — and that’s just the start”
SNIP
“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.”

thehill.com - Matthews illegal immigrants double under biden and thats just the start

SNIP
“Under President Biden’s watch, there have been over 8 million migrant
encounters nationwide, 6.7 million of which have been at the Southwest border.
Worse yet, over 1.7 million known gotaways—illegal immigrants who have evaded
Border Patrol— are now living in the interior of the United States without
documentation and without having undergone any vetting by immigration officials.
The serious national security concerns shared by Republicans have fallen on deaf ears,

budget.house.gov - Ogr icymi