Project transfer from Gitlab 11.4 CE to 16.0 CE

I want to transfer a project from Gitlab-CE11.4 to Gitlab-CE 16.0
I created a tar.gz export file in 11.4. The tar file contains project.bundle, and project.json files and a uploads directory.

Project.json file contains all the issues, comments etc and uploads directory contains all the images used in issues.
When import this tar files in Gitlab 16, only project files and wiki pages are imported. Issues are not imported. But since project.json file present in the tar contains all the issues, is there any way to import all the issues as well?
I do not get any error while importing but still issues are not imported.
There is also a separate option to import issues but that requires a CSV.