To nitpick: it's accurate to say that there is zero chance that the effect of psychedelics is just a placebo effect.

This does not mean that there is zero placebo effect involved with taking psychedelics. The latter statement would mean your experience is identical between actively taking a psychedelic and someone slipping some in your drink. I'd say this is unlikely, no?

We know for lots of other drugs, both therapeutic and recreational, that there is always a placebo component as well as a "real" one.

This is why people do placebo-controlled trials. You take 100 people and give them ibuprofen against joint pain, then you give another 100 people sugar pills against joint pain. Then you record their pain reduction on some scale, and the placebo scores 2 +/- 1 points, and the ibuprofen scores 7 +/- 1 points. So you say ibuprofen has a significantly better effect than placebo, but (probably) 2/7th of the ibuprofen effect is due to placebo.

Yeah, i understand that, but the point of a placebo is that you don't know whether you got the medicine being tested or not. I can assure you that you will be left with zero doubt about whether you received a psychedelic or not, unless it's a very small dose.

You're thinking of a blind study, strictly speaking a placebo is simply any pharmaceutically inert substance. You can take a placebo knowingly and in fact knowing that it's not medicine doesn't stop you from getting the benefits of the placebo effect.