Any idea on how I can improve this?

Here's an explanation about what's happening -
The command is - .tp ~ ~ ~; freecam; .tp ~ ~ ~; .setcheckbox .tp disable_freecam toggle

So when you press the keybind, first it sends .tp which just teleports you to the coordinates where you're already at.
Then it enables freecam.
Now it again teleports the freecam to the position where you're already at, and freecam doesn't turn off because disable freecam checkbox is unchecked.
Now it enables the disable freecam option.
Then after you move to the position to where you want to teleport and press the keybind again it sends .tp ~ ~ ~ which disables the freecam and teleports the player to the position where the camera is at because now disable freecam is turned on.
Now it opens freecam again but it gets closed again by the 2nd .tp ~ ~ ~ (disable freecam is still on) and it just ends up teleporting you to where you're already at
Now finally it unchecks the disable freecam checkbox and you can repeat the cycle again.

Also btw you should -

make sure there aren't many blocks between you and the position where you're teleporting
try not to tp over more than 100 blocks
try to keep the same vertical level, i.e., make sure your Y co-ordinate doesn't change drastically
make sure that you don't teleport into blocks, meaning that the freecam should not be inside any blocks when you're teleporting