Because if I'm a terrorist and I'm studying my enemy, I know there's pressure to keep families together.

Yes - but you don't have a family. You're just in a group of people that includes some kids - but they're not your kids. They're someone else's kids. They're not going to keep you together with them.

If I sum up everything you've posted, you're saying that there's literally nothing we can do except process 100% of the people who show up at the border and let them in.

Not at all. There's a million things that Congress could do to change the situation. They could modify the asylum laws to authorize deportation of asylees pending their claims. They could allocate funding for the construction and operation of new detention facilities that can hold several hundreds of thousands of people. They could allocate funding for more immigration law judges and attorneys so that these cases get heard quickly enough that we can just use the detention facilities we have. They could adopt the funding and legislative wish list that Lopez Obrador might want to solve this problem for us. Etc.

What I'm saying is there's virtually nothing that the Executive can do on his own to fix this. He doesn't have the legal ability to change asylum criteria or processes that are set by Congress. He doesn't have the budgetary authority to just build massive detention facilities. He doesn't have any of the tools that you would need to actually solve the problem.

Congress has the power to solve this, in a host of different ways. Unfortunately, the political incentives are such that as long as the GOP can successfully attack Biden for the issue, Congress is extremely unlikely to act.