Found the way to get Z pos in this uc post https://www.unknowncheats.me/forum/2089764-post3.html
If you want to teleport your current vehicle too set his position serverside otherwise wont work if you teleport out of your current stream range.
const teleportWaypoint = () => {
const waypoint = mp.game.ui.getFirstBlipInfoId(8);
if (!mp.game.ui.doesBlipExist(waypoint)) return;
const waypointPos = mp.game.ui.getBlipInfoIdCoord(waypoint);
if (!waypointPos) return;
let zCoord = mp.game.gameplay.getGroundZFor3DCoord(waypointPos.x, waypointPos.y, waypointPos.z, false, false);
if (!zCoord) {
for (let i = 1000; i >= 0; i -= 25) {
mp.game.streaming.requestCollisionAtCoord(waypointPos.x, waypointPos.y, i);
mp.game.wait(0);
}
zCoord = mp.game.gameplay.getGroundZFor3DCoord(waypointPos.x, waypointPos.y, 1000, false, false);
if (!zCoord) return;
}
mp.players.local.position = new mp.Vector3(waypointPos.x, waypointPos.y, zCoord + 0.5);
};
mp.events.add('playerCommand', (cmd) => {
if (cmd == 'tpm') {
teleportWaypoint();
return true;
}
});