Mt Chiliad was the highest point in GTA V and the centre of one of the longest-running fan mysteries in any video game. Leonida won't have one. Here's why and what fills the gap.
Why no equivalent
Florida is flat. Real Florida's high point is 345 feet. Leonida is built on that geography and cannot reasonably have a Chiliad-tier mountain.
Verticality has to come from other places - skylines, bridges, possibly construction sites.
What replaces Chiliad's gameplay
BASE-jumping moments may move to high-rises. Long aerial descents may use bridges or boats. The mystery-mountain pattern doesn't carry across - whether GTA 6 ships an equivalent secret-content tradition is unconfirmed.