Not sure where did you see only those phones you mention is supported. On the day of sim card collection. They put up several big poster at the Q area. At least some 60 phone type is supported. If remember correctly, Xiaomi model make up almost one big poster. My Xiaomi-Redmi model is listed, but not voice call. Even LTE support is on B40 TDD only. So coverage is like out door ok, inside building (shopping center) you can forget about it.
I am referring to VoLTE support.
https://www.tpgmobile.sg/topic/74-tpg-volte-supported-devices/
If just data, many models supported.
