I presently have no time to get into GR, but surely wish I did. Here instead of comment I offer two papers: Erik Lentz (underlying the work in the press release here):

https://arxiv.org/pdf/2006.07125.pdf

And similar seeming work by another group at something called the “advanced propulsion lab” (who are they?)

https://arxiv.org/pdf/2102.06824.pdf

It’s interesting that they both claim positive energy solutions that, eh hem, do the trick.