This isn't about securing the border or border encounters. It's about deportations. Apple and orange.
You're using a slice of data taken from SU TRAC (
https://trac.syr.edu/) and that data only looks at ICE deportations (actual ICE removals), not immigration court deportation orders. Which is why your numbers are low. Deportations are tied to a court order.
Expulsions are not. The majority of encounters lead to fairly quick expulsions with no court date.
The majority of deportations take years because they require a deportation order and for other avenues that may delay deportation to run thier course. If ICE moves to deport, but you have a court case with an immigration court, that's held until your court case happens. And in many cases there is other relief. But we're focused on deportations, so I won't go there.
Self-deportations don't factor in. Those are voluntary departures. A deportation is involuntary.
And despite any pauses, Biden's total numbers are fairly on par with Trump's. Ironic. The guy shouting for deportations the most was fairly milquetoast on that front, did it slapdash, separated family's and didn't specifically target the kind of MS-13 folks he whined about because he let Miller and Cucinelli just go ham elsewhere instead of focusing on targeted enforcement.
COVID and Title 42 helped Trump keep encounters low... Biden relied on that as well to drive expulsions. But those aren't deportations.
And the number you're looking for is likely 11.9 million. Total.