Chiefly, the resources that are necessary are the courts. That will indirectly aid the detention centers by clearing backlog. Spending more money there is actually more cost effective to improve the condition of these detainees at this time than increasing funding to detention centers. This is something that Trump has openly spoken out against doing and part of the reason for the lack of resolution to our extended government shutdown.
Secondly, asylum seekers are not criminals. They are people awaiting trial for a claim of asylum that, if found appropriate are allowed to remain in the States legally. The law does not compel us to detain them. It does compel us to hear their claim with some expedience, which in fact the Trump administration is failing to enforce much worse than ever. The law grants us the capacity to detain them awaiting trial. So the question is, when should we?
1. There is a question of deterrence. Separation does not deter asylum seeking. This ought to be evident by the increasing rate of border crossings despite current policies. It is also sound in principle, as good evidence shows that harsher punishments for offenses is ineffective at deterrence at all unless the punishment is extremely severe (e.g. death, losing a hand). I'd think what is happening might be classified that way. It would be for me. But of course I'm not fleeing a life-endangering situation in my home country. I guess it's not extremely severe for the people choosing to risk it.
2. So we are left with trying to ascertain what is the risk of people we allow to stay in the country awaiting a hearing and not detained. Principally, show rates for asylum trials are extremely high if not detained. For families, recent data shows about 82% show up for the initial hearing, 76% for all of them. Before Trump ended the FCMP, it was a resounding success, causing 100% adherence to court dates and 99% check-ins with ICE and case managers. So I think funding the FCMP to the point of universality ought to be the principle intervention to improve adherence to court. Obviously the more expedient the hearing, the likelier people will show, so again beefing up the courts is the principle thing to do.
Otherwise, I am OK if you want to detain adults crossing without children but think that it is also unimportant to do so. I am OK with separating families if there is a reason to suspect illegitimacy of the family relation and the children are not young (would need to work together to define the boundaries). I am OK if you want to add some form to enhance tracking people awaiting asylum claims. I am OK if you want to enhance security at the border through ICE agents and methods we have demonstrated as effective in enhancing border security, although that's a much bigger topic. I don't want those things, but I would be more than willing to work together with a goal of decreasing border crossings with interventions that have some reason to think they work.
More realistically, the best things we can do are in the humanitarian and international political sphere. A lot of US decisions have empowered Mexican cartels and oppressive regimes driving people to want to seek asylum and enabling drug trade. But that's a whole lot more complicated to get into and scraping the depths of my knowledge.
Furthermore I know that family separation at the border is as contentious as keeping families together. The site below details most of the complexity with either option, and it is no friend of the Trump administration.
https://immigrationforum.org/article/factsheet-family-separation-at-the-u-s-mexico-border/
I can't find anything on that site that demonstrates anything positive about routinely separating families at the border.