One idea: once more than half (or some other percentage) of the players are close to each other, show a circle on each player's map centered on the rendezvous point, and extending to the furthest player. The goal is to make it easier for players to figure out where they are, but without changing the gameplay substantially.
Regarding the circle idea: to make the circle less OP, we could make it only update either e.g. every minute, or when a player arrives at the target (in practice this tends to be spaced out quite evenly).
One idea: once more than half (or some other percentage) of the players are close to each other, show a circle on each player's map centered on the rendezvous point, and extending to the furthest player. The goal is to make it easier for players to figure out where they are, but without changing the gameplay substantially.