How to teleport Minecart with chests above a players head?
You must use ~ ~2 ~ instead of @p! If you teleport an entity to another entity the entity you teleport will always get teleported to the feat! But if you only replace @p with ~ ~2~ the minecart will be teleported to the command block! To fix that you must do it like this: /execute as @p at @s run tp @e[type=minecraft:chest_minecart,y=3] ~ ~2 ~
I hope that solve your problem!
Do you know you dont need to type /teleport! /tp will also work :)