It depends on what you want to use the fill for...when you define a fill, you are given 3 options: Drafting Fills, Cover Fills, and Cut Fills -- this determines which fills are available in the different dialog boxes. Gradient Fills are Drafting Fills and can be created with the Fill Tool only.
MacBook Pro Apple M2 Max, 96 GB of RAM
AC27 US (5003) on Mac OS Ventura 13.6.2
Started on AC4.0 in 91/92/93; full-time user since AC8.1 in 2004