For a warm and wiggly brisket, I like an electric knife. My son has one (don't remember the brand) that is sold to fishermen as a filleting knife. That one is especially nice.
For cool or cold brisket, a slicing knife with a Granton edge is good. Dexter-Russell has many options at very attractive prices.
https://www.dexterrussellcutlery.com/slicing-and-carving-knives/ Unless you just have to impress the neighbors, IMO the expensive branded knives are a waste of money. Dexter is what the pros use.