Update:
Went to T-Mobile with my ASUS_I005DA. Tried out a couple SIMs. My AT&T SIM gave me access to 4G and VoLTE. The T-Mobile SIMs gave me access to 4G+ and VoLTE. Unlimited data and hotspot access are a huge step up from my current AT&T plan, so I'm going to swap. However, I may hold off from ordering the ASUS_I005DC because I'm not entirely certain I'd get access to 5G in my area. I may just need to hold out for the US release.
Those 5G bands are global version not compatible with USA.