Frequency per client, automatic invitations
Weekly, fortnightly or monthly check-ins: set it once per client. A few days before each meeting the client gets an email to book one of the slots you opened. If they move it, you find out without lifting a finger.
Google Meet and Google Calendar, nothing else to set up
Every meeting comes with a Google Meet link created automatically. Connect your Google Calendar and turn the option on, and your personal events block slots so nobody books over them, while your sessions show up in the calendar you already use.
Exception dates and reminders
Mark the specific dates you don't work (holidays, time off) and the scheduler offers no slots on those days. Video-call sessions or your own meeting link, and a reminder to the client before each meeting.