Hi, I understand with you. Please you can publish it if it has not been published may be the conference organizers do not have Journal of their own to publish your work.

Tell the Editor in the cover letter and no problem

you present it , not published , I think you can publish it easily.

It is not unusual to publish a journal article based on a previous conference presentation, but the journal article should be longer and contain "new" things that were not in the conference presentation, such as additional categories of data analysis.

The conference paper and journal paper should not be identical.