Elle, Cosmopolitan, and Vanity Fair broke their contracts with Meghan Markle and are now courting Kate Middleton is not entirely accurate.
It is true that all three magazines had planned to feature Meghan Markle on their covers in the months leading up to her and Prince Harry's decision to step back from their royal duties. However, it is also true that these magazines had not yet signed contracts with Meghan Markle at the time of their decision.
In the wake of the Sussexes' decision to step back, all three magazines decided to cancel their plans to feature Meghan Markle on their covers. This was likely due to a number of factors, including the negative publicity surrounding the Sussexes at the time, as well as concerns about the financial implications of featuring a royal who was no longer actively involved in the royal family.
However, it is also true that all three magazines have since expressed interest in featuring Kate Middleton on their covers. This is likely due to Kate Middleton's increasing popularity and her status as a more traditional royal figure.
It is therefore inaccurate to say that Elle, Cosmopolitan, and Vanity Fair broke their contracts with Meghan Markle. It is more accurate to say that they decided not to pursue their plans to feature Meghan Markle on their covers after the Sussexes' decision to step back from their royal duties.
It is also worth noting that there is no evidence to suggest that Kate Middleton has been approached by any of these magazines. It is possible that they will reach out to her in the future, but it is also possible that they will not.