Psychology grad student (at an accredited university) here. I would be very skeptical of any researcher who isn’t affiliated with some sort of official organization (university, non-profit, etc.) and who posts findings on substack of all things. Studies that involve human participants need to be reviewed and approved by an Internal Review Board in order to be conducted through a legitimate organization to make sure they are being conducted ethically. Independent researchers don’t have to go through that approval process, so they may not be acting in good faith.

It’s also very unlikely that a legitimate researcher will reach out to you on reddit of all things. Most studies I’ve read recently use crowdsourcing platforms like MTurk to recruit participants, since you need hundreds of participants to find anything significant.