That list seems desktop centric - more browsing happens on the mobile. Hence Safari is a glaring omission on your list... Until Safari for iOS implements JPEG-XL, it is sadly not ready for mass deployment.
And it'll stay unsupported until those flags come on by default.
The point of the article is that Chrome removes the experimental, behind-a-flag support of JPEG XL, which dramatically decreases the reach of JPEG XL, so yo say.