Never place a anti exploit client side.
The server can get the cframe of the character.
Speed = Distance / Time – Detect any tp or speed
Using this simple equation can prevent tps as well as speed. To prevent flying or walking on client sided parts simply cast a ray. Keep an array that contains a few of the previous measurements and that will tell you exactly what is going on. You can also check the players spin speed from the cframe angles which can help check if they are being flung.
Dont just use one measure because its common practice, find whatever works best and use that.