Marketing is one thing and your appointments are another, and they are controlled separately. Unsubscribing from a studio's offers and newsletters does not stop your confirmations, your reminders, or a message telling you the studio has had to move your slot. Those are part of the booking you asked for.
The unsubscribe link at the foot of a marketing email applies to that studio alone. Other studios you book with are unaffected, and so is anything Friday Scheduling sends you about your own account.
Your notification settings hold the wider switches — email and text, marketing and reminders — if you would rather set it in one place than unsubscribe one studio at a time.
If a studio keeps sending marketing after you have unsubscribed, that is worth reporting. Consent for marketing is a legal obligation on them, not a courtesy.