LEWIS 4 to 7 is using nRF52840, this mean the hardware is capable of 5.3 and possibly LE Audio!
I don’t know what’s LEWIS 1 to 3 is using but i suspect N7 2019 firmware upgraded to LEWIS-3 HW/SW with part of LEWIS 4 SW platform for Android’s ASHA protocol. (Linx 3D HW/SW and Quattro SW platform hybrid…)