It depends what the cause is, which is really what you need to diagnose
If its the initial movement after construction, anything will do really, or likewise if its a known event on an old property, such as bashing something by mistake
If its movement however, either an old property taking on losing water with seasons, or an old/new property that has a moving joist or something thats far harder to fix. Typically fixing the issue first then fixing the crack is far better.
I tend to use the screwfix fine surface filler for most repairs and then the pre mixed plaster for large ones, such as the holes from removing tiles.
Caulk is ok if there is a very small amount of movement but you will tend to notice the paint cant cling on forever if there is repeated movement