Postgres Zip init not creating db user windows

Hi,
Ive downloaded the postgres extractable version of windows(32 and 64)
.These are the steps i followed

1.extracted the postgres zip file
2. create a new network user ( serviceaccount)
3. gave the owner ship permissions on the datadir
4. gave logon as service permissions to the user
5. ran the initdb

\pg_ctl.exe initdb -U myaccountuser --pgdata=datadir -o --pwfile=pswd
filepath -o --username=dbuser -o --auth=trust

Prob 1: By doing above the db is intialized with clusters and everthing..
but it is intializing the db as Administrator where the db owner is
administrator. The 'dbuser' is not getting created Im able to connect to
the db and see the users where dbuser isnt there

But ive to connect as dbuser .. one workaround is to create the user for
that db need to be started.This installation script dosent start db for me
and the createuser.exe in postgres zip is diff from installer version .

Prob 2: I also tried using runas myaccountuser but still facing the same
issue

While giving the --username option it has to supposedly create the dbuser
acc to my understanding.
Any other way to create dbuser while init before db startup

In linux the acc user itself is the db user so had no issues there ran the
initdb with su as accountuser which is the db user as well.

Here my accountuser and dbuser values are same..

Am I missing something here..

Thanks in advance

Regards,
Sagarika