Of course this trial is worse than useless if the other reported benefits of ketamine come from the experience had while under the effects, but these authors seem not to have thought of that.
And in fact, the study strengthens the idea that if ketamine works against depression, the conscious experience matters, because if you remove the experience using anesthesia, then it doesn't work.
Also, they didn't use any anaesthetic known to have antidepressant properties:
"Anesthesiologists were asked to minimize use of nitrous oxide (N2O), which has reported antidepressant effects22. Agents used for anesthetic maintenance included intravenous propofol and inhaled sevoflurane or isoflurane"
there are plenty of studies in which ketamine has been given without masking, so we have a lot of evidence it does help. You’re tacitly assuming that it does, which in the absence of blinding the patients to the use of ketamine there is no evidence for.
And in fact, the study strengthens the idea that if ketamine works against depression, the conscious experience matters, because if you remove the experience using anesthesia, then it doesn't work.