tanking is a bigger problem than the worst teams not getting the highest picks. you completely eliminate tanking by putting every team in the league in the lottery with equal odds except the two teams in the finals who will get the last two spots in the 1st round. all the first 28 spots are drawn too, if the worst team gets the 28th pick so be it.
The problem with your logic is even if every team tried their absolute hardest to win every game of the season there’s still gonna be bad teams. So how do those teams improve?