Removing large development files pushed in via Git-LFS after merging into master

I have used Git-LFS to push some big files into my development branch on During the development, I found out that those files are not needed, deleted them in my working copy, and pushed to the remote. As far as I understand, though, the actual files are still somewhere in a separate remote LFS storage, am I right?

Now, I would like to merge my development branch into master and delete it, and I don’t want the big, unnecessary files to be lurking anywhere in the cloud anymore. Is there a way to remove the unneeded files from the LFS storage without deleting the whole project? If not, what is the easiest way of recreating the project and preserving the history of the master branch (with all my developments now merged in), but not of my development branch?

Please follow the git filter-repo approach using the instructions in the Reduce repository size GitLab documentation. This approach will perform exactly what you are after.