ORLANDO, Fla — Months after Disney and Gov. Ron DeSantis’ appointees agreed to end a protracted legal fight, the two sides are set to approve an agreement that could result in the company investing $17 billion into its Florida resort and opens the door to a fifth major theme park at Walt Disney World.

The five DeSantis-appointed supervisors who oversee the Disney World district will vote Wednesday on a new development agreement that both sides had agreed to negotiate after a March…