These models of Apple Watch should report true for the rounded display corners setting:

appleWatchSeries4_40mm
appleWatchSeries4_44mm
appleWatchSeries5_40mm
appleWatchSeries5_44mm
appleWatchSeries6_40mm
appleWatchSeries6_44mm
appleWatchSeries7_41mm
appleWatchSeries7_45mm
appleWatchSeries8_41mm
appleWatchSeries8_45mm
appleWatchSE2_40mm (the name of this does not match the name Apple lists on the identify model page)
appleWatchSE2_44mm (the name of this does not match the name Apple lists on the identify model page)
appleWatchUltra
appleWatchSeries9_41mm
appleWatchSeries9_45mm
appleWatchUltra2
appleWatchSeries10_42mm
appleWatchSeries10_46mm
appleWatchUltra3
appleWatchSeries11_42mm
appleWatchSeries11_46mm