My opinion in an ideal world is to bring back asylums but do it proper this time with careful consideration for due process, checks and balances, and fair conditions.
But the realistic side of me knows that's a big ask and doesn't trust the government to do anything right.
There's also a part of me that thinks, for certain crimes it's a [I'm drawing a blank on the word here] that you're mentally-ill because no sane person would do ___________ and anyone that does ________ should be in prison.
Ultimately I think asylums for the ones where there's no hope of improvement or that become murderous when off their meds, and remote rehab facility type things for the ones that are less serious.