Hello there, I am new too. My 30 year old son suffers from chronic, treatment resistant Paranoid Schizophrenia. I have lived through the chronic suicidality and crippling depression that comes with this illness. I am his sole carer and all of my family are 600km away.
I am actually a highly experienced psychiatric nurse, however all the knowledge and experience are useless or get in the way when you are dealing with your loved ones.
One thing I have noticed with my son is that he has trouble picturing things changing or looking at and planning for the future in any way. If your beloved daughter has the same problem then I can understand her suicidality, if she is unable to see that things change. It breaks my heart to hear what you are going through- I was horrified to read the heading of your post. I am actually trying at the moment to look for help and support for myself because I am falling apart a little bit here.
One thing I will say and it probably will feel useless at the moment, but my son is involved in an excellent group called Hearing Voices which is peer run and serves to help people diagnosed with schizophrenia to take some authority over themselves rather than feel powerless at the mercy of the mental health system- which is completely broken by the way. Its worth googling I think. Also I'm not sure where you are located but I think your local Primary Health Network also provides community support in quite a few ways. I really believe that for people with schizophrenia community connection is the most important thing. I understand that this feels like useless information when your daughter is so suicidal, but in my experience with schizophrenia that suicidality is always in the background. I found my son researching assisted death machines online only a few months ago.
So sorry I can't offer anything more useful, but what I am slowly learning is that I have to take some of the focus off my sick adult child and find ways to have meaning for myself (gardening is my thing) and people to talk to. i have observed that my son is very responsive to whatever the mood is in the home, and so the more functional I am the less stress and worry and grieving I am generating the better he functions. I am also trying to stop my son and his schizophrenia from being the primary focus in the household every day which is a challenge because all I do is stress and worry and grieve. Hang in there; my heart truly, truly goes out to you and I wish you strength and courage and self love, and that you and I and as many others can avoid becoming statistics.-
One more thing regarding medication- my son said to me once that the psych drugs they insist on using made him feel that his soul was dead inside of him. I watched as before my eyes he gained 35 kg on their favourite drug, (which starts with a "Z" and I'm apparently not allowed to mention it in the post) which is the drug everybody gets regardless. And I do believe that at this point in time mental illness is not considered in the current legislation around assisted dying, let's just hope and pray it stays that way
Anyway hang in there, make sure you have enough support as possible which is what I'm in the middle of doing now. All the very best to you.