You're still rebasing your branch onto main (or whatever you originally branched it off of), but you aren't then doing a fast forward merge of main to your branch.

The terminology gets weird. When people say "merge versus rebase" they really mean it in the context of brining changes into main. You (or the remote repository) cannot do this without a merge. People usually mean "merge commit versus rebase with fast forward merge"

Here's an example

Say I work on authentication under feature/auth Monday and get some done. Tuesday an urgent feature request for some logging work comes in and I complete it on feature/logging and merge clean to main. To make sure all my code from Monday will work, I will then switch to feature/auth and then git pull --rebase origin main. Now my auth commits start after the merge commit from the logging pr.