I know, this is the only carrier in Poland, which uses a whitelist to volte works, however, volte/vowifi on zenfone 8 works correctly only In Orange 😕 But with code and only in flex virtual brand. In this term, T-Mobile is waaay better, but Asus added a broken volte configuration for T-Mobile (maybe only in Poland, I haven't seen any posts with problems from other people), and doesn't do anything with this.