A branch is a 41-byte file holding one commit name; it moves when you commit on it; making or deleting it does nothing to the commits.

Cheap branches are the reason Git workflows look the way they do, and "deleting a branch deletes work" is false.

People picture a branch as a copy of the project. It is not.

A branch is a note with a name. It points at one commit. On disk it is a file holding that commit's name. Forty one bytes.

Commit again, and the note moves to the new commit. The commits stay where they are.

Making a branch writes one small file. Deleting one removes the note. The commits it pointed at are untouched.

So a branch is cheap. Make as many as you like. The history is the commits. The notes just mark places, and only move when Git moves them.

Check yourself. You delete a branch. What happens to its commits?