add public_read env after upload with duck cli using powershell

[MDroog]

I can't get it done to do a duck --upload adding public_read props to the uploaded files. the documentation states using env "s3.acl.default=public-read" duck --upload https://docs.cyberduck.io/cli/#uploads-with-upload
but cannot throw that into a powershell command, wanting:
& duck --upload $S3fullPath "$updatePath$filename" --existing overwrite --username...