It's really difficult to risk assess people, and to make that regular enough to pick up changes.
For example, Mental Health teams (of all sorts) do not prevent their service users committing homicide/ suicide, even when they are working well and having regular contact.
I'm not against better risk assessment, but it is difficult, and not foolproof.
It is not an easy fix.
Ultimately when it comes to homicide/suicide changes to firearms regulations are going to be marginal at best - we already have fairly robust regulation in that respect which reduces the crossover of people with that intent and having access to firearms and without a gun by and large most of those people will still go through with it at some point one way or another.