Who would give you the higher chance to win a title in the next two years? You as the manager already have a team which is solid in defense and solid in offensive, but it lacks a star player to make it a serious contender. You can either add Embiid or Doncic to that team.
Luka has shown to always level up in the playoffs, which is crazy considering he basically puts up 30-9-9 during the regular season. If you surround him with a team of good defenders to cover his weaknesses (like the Raptors), I believe he can win a chip.
Embiid legitimately gets worse in the postseason, and has no memorable playoff moments to speak of and he’s almost 30. And unlike Luka, Embiid has played with elite rosters.