I'm just curious Rob's youtube video on audio editing with a NAS.
(Choosing the Right NAS CPU for Audio Editing - Buyers Guide
There is no Audio editing app for NAS per say. But if you do want to install it directly on the NAS, then plus series NAS like DS218+ or TS-251D would allow you to install Windows virtual machine. Then you can use well know software the usual way. You can then connect to your NAS over the internet and do the editing.
But if all editing will be done locally then you may map a network drive to your computer. Or if the software do not allow using network drives then you can set up ISCSI volume and mount that. This would trick software thinking it is actually an internal disk.
I hope this helps.