bro i think dota no need concern more about hz since it not that 3d and just a moba game.
so i think should more concern on color. 144hz monitor is over the budget that u only wan use to play dota

V-sync will set your FPS to 30 when it drops below 60.

U probably mean screen tearing when u say 'graphic choppy', which is happens when your FPS & monitor timing is off.

Example:
If you have 60hz/120hz monitor, acceptable fps with no tearing = 15, 30, 60, 120, 240.

Problem with V-sync is input lag, meaning what you see & your mouse/keyboard becomes unresponsive, that is only if you can feel it. If you don't, no problem.

Solution summary:

Try adjust settings to get slightly above 120 fps, then cap fps at 120. (Set fps_max 120).

If cannot hit 120 fps, try fps cap at 60 instead of using v-sync.