If you poke around under the hood of your Samsung Galaxy Note 8, which at this point is a tad dated, you’ve seen under WiFi calling there’s been an option forever for Voice Over LTE (Beta) forever.
If you wanted to test that out you would have been able to do voice and data at the same time, and you would also have run into Sprint’s really really terrible handling of VoLTE. It’s something I had to turn off long ago because it sounded like I was attempting to impersonate Mer-Man from Masters of the Universe.
Today I woke up to a Pandemic surprise and there was an update waiting for me that auto implements it. We’ll see if I can still sound like a second tier MotU villain when talking to work.
If you need to disable it you can find it under settings, connections, Voice Networks.