Remove a directory created by a container (permission issue)

Hi,
I run a code inside a container that creates an output folder and many other folders inside, I mounted the data into a directory using -v.
The output folder is created but I can’t remove it as it belongs to the root.

I added my user to the dockerfile as following:

RUN addgroup --gid 1001 uname
RUN adduser --disabled-password --gecos "" --force-badname --gid 1001 --uid 1002 uname
USER uname

After that, I could remove the output folder, but I can’t write on it.
What shall I add to the dockerfile or when I run the container to give all permission to my user?

Thanks