Sabine Hossenfelder is a physicist, cosmologist and non-theist. This latter point is relevant because in the short video below she criticizes the multiverse hypothesis which has been near and dear to non-theistic hearts for at least a decade now, so her criticisms cannot be dismissed as being based on some sort of religious agenda.
The multiverse hypothesis enjoys the approbation of those eager to squelch any hint of a God behind the universe because it provides a rebuttal of sorts to the theist's argument that the fine-tuning of the universe is powerful evidence of intelligent engineering.
Hossenfelder avers, however, that the multiverse hypothesis is itself religious, largely speculative and outside the bounds of empirical science. This is not to pass judgment on whether or not it's true, but rather to point out that scientists, qua scientists, have no business promoting it. When they do, and they do it often, they're stepping outside their proper domain into the domain of metaphysics and forfeiting whatever scientific authority they may have had.
There are lots of posts in our archives cataloguing the numerous reasons for doubting that the multiverse explanation is correct, but Hossenfelder is here concerned merely with getting it out of the realm of empirical science and into the realm of religious belief where it belongs.
The video is about four and a half minutes long, but she packs a lot into those four and a half minutes. Give it a look:
