Creates a user account in Microsoft Remote Desktop 10 under Preferences > User Accounts. Modify the necessary items under the "set the keychain item attributes" and run.

Add Remote Desktop User Account.bash

#!/bin/bash

# set the keychain item attributes
account=$( uuidgen )
accountName="serveradmin" # aka label
accountPassword="MySecretPassword"
applicationPath="/Applications/Microsoft Remote Desktop.app"
friendlyName="Server Administrator"
service="com.microsoft.rdc.macos"

# stop the script if Remote Desktop is running
if [ $( /usr/bin/pgrep "Microsoft Remote Desktop" ) ]; then
	echo "Microsoft Remote Desktop is currently running. Quit the application and try again."
	exit 1
fi

# get index number of last user account
lastUserAccount=$( /usr/bin/sqlite3 "$HOME/Library/Containers/com.microsoft.rdc.macos/Data/Library/Application Support/com.microsoft.rdc.macos/com.microsoft.rdc.application-data.sqlite" "SELECT Z_PK FROM ZCREDENTIALENTITY ORDER BY Z_PK DESC LIMIT 1" )

# create the keychain item
/usr/bin/security add-generic-password \
-a "$account" \
-l "$accountName" \
-w "$accountPassword" \
-T "$applicationPath" \
-s "$service"

# modify the SQLite database to reference the keychain item
/usr/bin/sqlite3 "$HOME/Library/Containers/com.microsoft.rdc.macos/Data/Library/Application Support/com.microsoft.rdc.macos/com.microsoft.rdc.application-data.sqlite" "INSERT INTO ZCREDENTIALENTITY (Z_PK, Z_ENT, Z_OPT, ZNILPASSWORD, ZFRIENDLYNAME, ZID, ZUSERNAME) VALUES ($((lastUserAccount+1)), 4, 1, 0, '$friendlyName', '$account', '$accountName' )"

exit 0