Breaks
Focusing on a digital meeting is just as tiresome as s real life ditto, if not more. Here's a recommendation that doesn't regard any Zoom feature but the virtual classroom format itself.
Additionally to the lunch and coffee breaks, try to give yourself and the students 3-5 minute micro breaks so that no session is longer than one hour.
Be sure to uphold the discipline for these, always communicate the exact time on which your lesson continues, and always start on time.