Toxicity is measured by the amount of something that is slightly harmful to the body. Life is slightly harmful to the body yet we all live. I'd say if you are having challenging trips one after the other it means that you did not learn the lesson from your first trip and got punished on the next one. In my opinion any psychedelic should be used for personal growth and if you are not growing that much from them its time for something else.
May wisdom permeate through your life.
"What is survival if you do not survive whole. Ask the Bene Teilax that. What if you no longer hear the music of life. Memories are not enough unless they call you to noble purpose." God Emperor Leto ii
"The only past which endures lies wordlessly within you." God Emperor Leto ii