It depends on what you want really, but my answer is, well, kind of, but not really.
With ketamine you guarantee ego death with the ease of one line up your nose and about five minutes of waiting time. It's weird, confusing and certainly one to lose the ego with ease and experience some strange strange places.
The thing is, whilst not having personally tried ayahuasca, I don't think it's really in the same league as tryptamines when it comes to spiritual effect.
With tryptamines or salvia you can be left thinking 'did that actually just happen?'. With ketamine you tend to come back to baseline and know/think it was just a trip. Quite often you wouldn't want it to be real. With ketamine I've felt I was at the gates of both heaven and hell many a time, but it does seem somewhat artificial, unlike DMT and Salvia.
That said, I do have a habit of thinking I am reliving a salvia experience I once had, and consistently think music is being "beamed in" with ketamine. In the immediate aftermath it all seems very real, but after that the spiritual effects subside and I don't really feel in any way altered the next day.
It's certainly one to try though. I wouldn't discredit it, but would certainly tread lightly seeing as you were addicted to DXM. Ketamine can be very addictive. Then again it was, until recently, widely available and cheap in the UK. Made it hard to avoid.
Put it this way, I've seen people take ketamine on hundreds of occasions, and although on a few of those occasions people were convinced something spiritual happened, I have never ever seen people come out of a k-hole with the kind of lasting spiritual effects that I've seen but a few people come away from ayahuasca with.
Ketamine: Psychedelic, dissociative, ego-less, but not particularly spiritual.