Is it possible to take two cameras?
When I go out to casually shoot something in my own time, I take one camera and shoot on manual: the usual mode of operation, I assume, for most occasions.
When at an event, however, it can be useful to carry two: one is set up fully (or mostly) automatic in order to allow you to quickly point and shoot at interesting, quirky, unmissable etc shots. This camera should be in your hands 90% of the time while moving, but likely less than 25% of the time when deliberately shooting. eg it's always ready, sometimes used, but not the preferred option. It allows you to capture as much as possible of the day, and never miss an opportunity.
This first camera is set up to be as automatic as possible, with a fiarly middle-of-the-road lens: something like a 55-300mm, to allow you a decent amount of scope to capture anything that comes up within a couple of seconds. An optional flash would be preferred. Your aim with this camera isn't to capture perfect shots, it's to capture context and "supporting" shots. Your post-processing will help.
The second camera is your manual/mostly manual/semi-automatic (depending on how you like to shoot) camera, presumably also your better unit. This is the one you swap lenses, set up specifically for each shot, and use for your set pieces. You carry various lenses, flash options if needed, and you know this camera inside and out. This is the camera you use whenever you know you've got a moment to set things up, for the family and group shots, and for the "showcase" front cover, big photos... the "wow" stuff that people come to you as a photographer for, the artsy photos of the cakes, the beautiful photo of the couple under the trees etc etc
This allows you a great combination of the highly professional shots you're hopefully known for, along with lots of context shots from which you can choose the best, capturing the spirit of the day as well as the highlights. It also means you don't miss the comedy shot of the groom and his nephew sliding on his knees down the hotel foyer at the reception, with the bride looking on with a perfect "Oh well, it's too late now" look on her face