Gitlab LFS migration doubles reposize

Hello everyone

I have a big repo on (8GB) with some assets (textures, etc). I decided to use git lfs for the sometimes above 50MB files.

I started with
git lfs migrate import --include="*.png"
and did
git reflog expire --expire-unreachable=now --all
git gc --prune=now
and tracked the filetype (track, commit .gitattributes, push)

The problem is, that my repository size nearly doubled and I cant push new content, not even the .gitattributes because of the 10GB sizelimit

How can I tell git, that git lfs has already track of the .png files, and that the original versions in the repo can be deleted? (I thought that migrate would exactly do that … but it doesn’t)

Thx in advance

Update: I did a testrepo with just 1 bigger file. And the outcome is the same. I have doubled the repo size, because the file seems to be in the normal repo and lfs at the same time. In it is shown with a lfs tag tough.