This. This right here:
Do not start the presentation with an apology or disclaimer.
No matter how much more you had hoped to present, by the time you get in that room, whatever you have is exactly the right amount of work. Any resetting of expectations should have been handled before the meeting.
I worked with someone who routinely started client meetings with an apology. It used to drive me nuts. There are things on this list that I do sometimes when working a room, so I’ll have to brush up on this before my next presentation.