I cannot verify safety for you. Psilocybin work while you use alcohol and take venlafaxine is not straightforward, and safety depends on your history, dose, setting, and clinical supervision.
Venlafaxine is an SNRI. Reports suggest SNRIs may blunt the subjective effects of psilocybin, and medication changes should only be made with your prescriber. Do not stop or adjust venlafaxine on your own.
Alcohol use can complicate preparation and integration, and some facilitators ask people to reduce or pause drinking before any session. If alcohol is a coping tool, address that supportively in therapy regardless of psychedelics.
If you are considering this, talk with your prescribing clinician and an experienced facilitator to review risks, goals, and timing. For a concise perspective on sessions with psilocybin, see this overview: psilocybin information.
Wishing you clarity and safety.