Why be easy when it can be complicated? Why use third-party applications like netdom.exe when correct interogations is the way? Try 2 interogations:
wmic computersystem where caption='%computername%' get caption, UserName, Domain /format:value
wmic computersystem where "caption like '%%%computername%%%'" get caption, UserName, Domain /format:value
or in a batch file use loop
for /f "tokens=2 delims==" %%i in ('wmic computersystem where "Caption like '%%%currentname%%%'" get UserName /format:value') do (echo. UserName- %%i)