Compounds and polishes differ by abrasive size and how it breaks down. A cutting compound removes defects fast and leaves haze. A polish refines that haze to gloss. A finishing polish or glaze addresses the last five percent on dark paint.
Modern diminishing abrasives do both jobs in one bottle to varying degrees, which is why a one-step product is realistic on soft paint and optimistic on hard German clear. Match the compound to the paint, not to the review.
Every listing states cut level. Test on one section, inspect under proper light, and adjust before you commit to the whole car.