Things may be different now, but worth noting that this approach was proposed for LSD research about 20 years ago and FDA was not supportive.
To me, this doesn't sound like a good use of money for a start up. But, with adjustments, it could be a good basic science project for an academic lab.
I think it would be much simpler in terms of ethics and regulatory red tape for a group not doing drug development (like the Hopkins or UChicago teams) to fundraise for study based on the RDoC framework. A study designed with this framework could look at general therapeutic effects that cut across diagnostic categories.
Having participants pay would be ethically perilous, but this should be relatively easy to raise money for. Arguably, the dubious work Fadiman and Stolaroff and crew were doing in the 60s can be read as an example of how having participants pay distorts incentives.
And using an investigator-initiated vs drug-company-initiated application emphasizes that this designed as basic research, which, given the statistics of heterogeneous samples, more likely to yield new hypothesises than conclusions.
Link to RDoC framework: https://www.nimh.nih.gov/research/research-funded-by-nimh/rdoc/about-rdoc.shtml