No, The U1 firmware naming is a LITTLE bit different than the U versions of the firmware. It's still the Snapdragon (Otherwise we couldn't use it) the "S" is a Security Patch.In this firmware version, does ES stand for a certain processor?
S2DUH3 is a Security Patch,
Bootloader 2,
Build "D" (Android 11),
"U" 2021,
"H" August,
"3" build number 3
Honestly, I don't know what the "E" Signified