I don’t think you can beat Musk with a poison pill if he decides to buy.... Even if others can buy highly discounted, Musk can literally pay full list price and keep buying.. if he so chooses.
The question is, what are Elon’s motivations.. if its purely a profit play in the shorter term, this sort of move might convince him to move on...
If his motivation is he truly wants to make sure Twitter is open.... and its more ideological than profit based, he can afford the any short term hit that higher prices might cost him.
And he is building a satellite free speech web network that could be in future plans.