Segwit did not break covert asicboost. The math proved that wrong, and that one could make very small, inexpensive changes to have it continue working with segwit.

This was admitted by Greg Maxwell in the dev mailing lists, when they proposed an asicboost blocker only change, that they rescinded because they realized that it and segwit never actually stopped covert asicboost.

It was also confirmed by experts like chjj (CTO of purse.io, and Bitcoin developer) that segwit never blocked covert asicboost.