Technically, making tulpa would be considered DDNOS, except that the new definition exempts shamanistic practices. Making tulpa is a shamanistic meditation technique practiced in Tibet for the purposes of self-discovery. It takes years of focused practice and concentration, but self-hypnosis can help some.

This modern resurgence of tulpas seems to be trying to find faster ways to make them, with less then years of effort. The evidence for success in this is so far anecdotal. I would advise caution - this is not something that would suit everyone.

I have made tulpas in the past. I've some that are decades old. I will say that seems to be rare so far. Also, in my observation, tulpas become odd after decades, acquiring just as many quirks as most humans have. I personally don't think that there is as much risk of insanity as people think, but I would err on the side of caution myself.