I was talking to my mate about this the other day, in the context of kiddies dying young. We decided the only way we could square this with a loving God was if this life was actually unimportant in the scheme of things, like a day at infant school. Of course if you don't believe in some form of God that's not an argument, but then nothing is.
Personally I think we come back many times as one life doesn't teach you enough. (And no, I wasn't a Rag in a previous life.) I don't think punishment comes into it BTW. You live to learn and some lessons are harder than others. Just like school.
Whilst I don't quite think about things in the same way as you, we think in similar lines.
Whilst I have had my own conflicting experiences of 'death' and what happens after, I'm of the thoughts that people get confused with this life and the people that have come before us.
All I can think is that we can't know the amount of life out there beyond our galaxy/ solar system/ universe. Life, that existed up until now, can very well be a drop in the proverbial ocean because our concept of time and existence is a Human concept enshrined in Human limitation.
My experience was very much spiritual and my 'return', shocking. Spiritually, you KNOW there's something more. Logically, you KNOW there's something more also. The two are not mutually exclusive.
For me, we learn what we learn on this plane and take that forward. Before now, I have encountered so many of the same situations with people and not realised I had to change something in order to move forward and not ask 'why the fook does this keep happening to me?'!
It's the same as 'deja vu' in that case, that we've faced similar things before and we have to learn from it. A redo of the same life? A repeat of a situation from a past life? Is this 'string theory'? Who knows?!
Life, is not complicated; we live, we die, that's it.
Existence is SUPER complicated as we exist on so many levels: consciously, subconsciously, spiritually, emotionally, mentally and physically. There's also connection to the earth and what's beyond (i.e., the yearning for knowledge of the 'unknown').
I didn't get to 'Heaven', so I couldn't tell you if it actually exists, but my feeling has never changed in 30 years that there's more to this world than we tell ourselves.