When sysprepping Windows, before final shutdown:

• open powershell/cmd and admin, cd to C:\windows\system32\sysprep

• unplug the Ethernet cable/disconnect from Internet as Windows 10 will install apps on temp admin account which can cause sysprep to fail

• do a sysprep → audit → reboot

• then delete all local user accounts/profiles

• in Win10, goto settings → Update & Security → Device encryption → make sure bitlocker is turned off

• then generalize and oobe