I had an experience with nitrous and marijuana where there was no "I" yet I don't know if was profound enough to be considered an ego death. I guess that's up to me to decide.

I was nothing being nothing floating in nothing. Yet I wasn't floating because I was nothing. And I wasn't I because I wasn't anything. It was really hard to wrap my mind around. Also really brief.

Then I learned all the knowledge I know as I came back and learned about myself.