A new release of exfatprogs is now available as the user-space programs on Linux for the exFAT file-system to complement the in-tree kernel driver for the Microsoft exFAT support.
New to the exfatprogs 1.3 release is introducing defrag.exfat as a tool for defragmenting an exFAT file-system or assessing its fragmentation status. Thus now defragging exFAT under Linux rather than no defrag support at all or having to do so under Microsoft Windows.
Note that you need to use disk space to describe where all the slices of a file are. There are some limitations to how many pieces your files can be in. Not sure on exFATs limit, but on NTFS I know it’s a soft cap around 1.5 million parts.