If you intend to purchase the Google Pixel 7 series of phones and use it with SIMBA (formerly TPG), the bad news is that, you will need to use the SIMBA voice app to make and receive voice calls. Although the 5G option is selectable, it is not known if 5G NSA will work on the Pixel 7 Pro on SIMBA.
VoLTE function is not provisioned on SIMBA except for Pixel 4 and 4a. Hopefully, they will push an update to the firmware to enable VoLTE across all Pixel devices (including Pixel 2,3).
In fact, it took them 3 years to enable just a VoLTE function for M1, another telco in Singapore. It is only recently they enabled 5G SA on M1 as well.
I am sure there are many pixel worldwide users do not have this basic VoLTE turned on. Comment below.