It depends a lot on what you want to photograph. For the direct moon and sun coincidence you can preset exposure by putting a suitable (and substantial!) neutral density filter on the lens and aiming it at the full sun. That will cover you until you get within totality.
I used all manual settings in 2017. It's even recommended to tape the focus ring on the lens, as autofocus will get lost somewhere along the way, and working at some weird upward view in the dark is tedious enough! I know I lifted the solar filter off during the 2 minutes or so of totality, but don't recall any exposure adjustment. Probably even spot metering would be extremely difficult to produce anything meaningful, and somewhat depending on where you're shooting from, the totality phase is quite short just a minute or three.
Another problem I found was that at high magnification there is surprisingly rapid movement and it was extremely difficult to figure out where the frame was when trying to recenter the image. Probably a geared head with one axis set to parallel the path would be cool -- or a full-blown clock drive as used for general astronomy. But for using once every decade or two, that's a lot of overhead.
If you wanted to include a broader view and see some peripheral detail, that might suggest a bracket, bracket, bracket approach. But consider that at near totality you are looking at a huge scene brightness ratio situation.
(See -- I did it once and now I'm an expert!
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Edit: In the gallery page at the above link, the first two thumbnails open sub-galleries with (manually timed) interval shots.