>>282274649
Unfortunately, CSM’s manga sales are 30 million copies worldwide including Japan. (Since no other numbers have ever been annouced, it’s reasonable to assume that this figure represents the total global sales.)
Meanwhile, the overseas-only sales for other series are: One Piece and Naruto at 100 million, Demon Slayer at 50 million, and MHA at 40 million.

Even if we assume, hypothetically, that CSM’s 30 million sales were 0% Japan and 100% overseas (which is obviously impossible), it would still be behind all of the above series.
Realistically, CSM’s overseas sales are probably somewhere between 15 million and 5 million at best.
With that in mind, it’s hard to argue that CSM is especially popular in the West compared to other manga.