She instinctively bonds and draws from the death she causes which slowly but surely restored her connection to the Force, this was still happening beyond her battle with Traya as Darth Sion concludes that Surik had the potential to surpass Darth Traya.
The years following Malachor V saw Meetra lead the reestablishment of the Jedi Order to a triumphant return to the Jedi Temple. She trained many new apprentices in that time and so obviously had much experience and wisdom to fulfill whatever potential remained in her.
Meetra isn't some constant draining presence in the way she is misrepresented, the context of all those statements about her bond and draining ability only leads to the full restoration of her ability in the Force. Zez-Kai Ell explains that, but everybody loves ignoring it.
The Dark Side Exile can infact properly drain from her friends and foes alike, becoming far stronger.