How to induce a nde like experience
 

i'm looking to have near death experience without putting my life in danger

I'm sorry but the whole meaning of a near-death experience is just that -near death. It is usually a natural occurrence, not one which can be forced in any way. I have no idea what could happen if one was forced. Also there is the practical problem that we are not usually capable of killing ourselves and returning. That is a fine line.

This has started to remind me of the movie "Flatline"....

I may be wrong, but maybe that's not even what you're looking for? You are looking to experience your multi-dimensional Self? Right? That can be done without putting your life in any danger. What you are seeking is an expansion of consciousness. That can be done through meditation and possibly also out-of-body experiences and Astral travel. Or even a great change within you and a different perspective, regardless of the phenomena which may, or may not be attached.
One can see the Stars without ever having to 'go anywhere'. It's a heart-known thing.

When we do eventually cross over we walk with a Grace, and all is well there.

I think you probably don't want to try to induce and NDE... An OBE (out of body experience) will feel very similar in that you can view your body and so on though.

Why do you want to have an NDE?

I've heard ketamine could work

This all sounds decidedly reckless to me and most unwise.
These aren't phenomena to be played with.

There are plenty of books on the subject, first hand accounts from people telling their experiences.
If you want to learn about NDEs, this is the best way!

PS: Have you considered counselling? This matter has been eating away at you for quite a time now. It's not healthy.

I don't need counseling or hearing about people's experiences I need real answers, having an nde seems to be my best way of getting them

There is a line as thin as a hair between killing yourself permanently and being able to return to the physical body. I doubt if anyone has the ability to measure the limits, and control the events as finely as that. Once you go, there is no changing your mind. You will be a suicide victim, and have to bear all the ramifications of that. For the sake of an experiment and a vision into the next dimension - do you really want to go down that route??

Astral travel will give you a wonderful view of the next dimension! You can have some amazing experiences, visit loved ones, or those who have passed over, or other Beings....etc.
Astral travel is a real thing. Even a most basic out-of-body experience will show you the immortality of yourself. It's not any kind of 'hallucination'. You'll see anyway when you get out!

If -seriously now -you are depressed, then that needs some attention. It is an illness, and needs professional help.

Why do you think I've been so obsessed with trying to find out what happens after death in the first place

I can completely understand your need to know what happens after the death of the body. Not to 'believe' not to 'imagine'....but to know. Most of us are at least curious, many of us have quite set ideas, some of us don't have any idea. It is one of the mysteries. The only reason it's a mystery is because for some reason when we come down here consciousness enters a very dense phase. That often baffles me, but I do realise that 'dense-ness' can be overcome at least in part, by expansion of consciousness.
I also feel that there are other aspects to the after-death state which we can only know when we go there -naturally, and permanently.

I have been given glimpses of the life beyond, and those have brought me much happiness. Yet I realise those lovely glimpses were from a clear minded, natural and innocent Soul whose Heart was full of love, and who lived this life for its own sake, and to the bitter end, with grace
.
I have also been given glimpses of incredibly dark/cold/horrible conditions (which I was given to envision from late childhood, but have only in the last few years begun to understand what those things were. They were Astral Worlds which I have experienced before and have no wish to return to.)
I look on those memories as visions into choices, and what I decide to do with myself, my consciousness -in all dimensions, and my energy-field. Those are states I have already known before, and I heed their warnings.
No -not 'punishment'....but simply like to like situations!

I have no logic parameters about it. Only my intuition and what I have glimpsed. Memory has been my teacher in one respect....Love in another and much greater respect. (about which I am still learning day to day.)

There are layers upon layers out there. There are literally billions of Astral situations. I would have no wish to gamble in any way with what may happen to my own Soul. Trying to outwit our own mortality, and our choice to enter the dense physical, may backfire. Yet our choices are our own to make. Our journeys are our own. No-one can tell us what to do. We have to find out ourselves.

Intent is everything in the Inner Worlds. It's wise not to forget that.