Not sure how sarcastic you are, but I could see work camps being built. I think we’d see some deportations and some people sent to work camps, but not a complete crack down. Just enough to make it a threat.
It’s not just the logistics of moving that many people that is a problem. It would be extremely damaging to the economy. Undocumented labor makes the food we have as cheap as it is (along with government subsidies). If that labor pool evaporated we’d see more widespread issues with food rotting before being picked and food not getting processed.
The work camps would take the form of farms and food processing plants, possibly expanding to other manufacturing later. Free slave labor is how we’d compete against the slave labor in other countries. It’s important to note that managing that takes up a lot of resources, so I’d expect the majority to not be rounded up and sent to these camps. I’d expect the threat of being sent to a camp to be used to extract lower pay and more hours out of the existing undocumented population that works in those industries.
Having these populations still intact would be useful to instigate more crackdowns as political events to provide a boost.
The main problem with these camps (and existing populations) is that people have kids even under the worst circumstances. That is why we’re seeing the talking point to remove/overturn birthright citizenship. Eventually the camp population would be almost entirely us citizens which makes things less tenable. So they’d need to remain different so it’d be okay for them to stay in the camps they were born into.