"(free space)" listed in diskutil list after deleting a partition

I am using an m1 Mac mini, and recently tried installing the ash linux alpha. After a bit I decided to delete it. But I realised that the space I had originally assigned to the partition hasn't been reassigned to the existing Mac partition. I also don't know how to force the merger of this free space since I'm not sure how to refer to it when using the mergepartition command. Here is a photo of the terminal after running "diskutil list".

Any help greatly appreciated and thanks in advance.