I am using a Mac Studio computer with KEF LSX II active speakers connected by USB. Although KEF state that their Connect app is for mobile or tablet use, I have successfully installed the App on my Mac and have been using this for nearly 2 years. Recently I noticed that my Mac would shortly be running out of disc space. The KEF library file had grown to over 250 GB. Using a third party application I deleted the respective Library folder and recovered the lost storage space. Probably my fault for misusing the Connect App. However, I will continue to run the App on my Mac but this time keep a watch full eye on the size of the KEF Library file.
Very strange phenomenon. I have also been using the KEF app on my Mac Studio for quite some time. In my Library, the KEF files hardly take up any space! The difference with your setup is that I have connected my LSX and LS50 speakers to my home network via Ethernet to work well with Roon.
My setup is hard wired in a similar way. I agree the KEF Connect App itself takes very little space typically 63 MB on my Mac Studio. After some head scratching I located the hidden 250 GB KEF folder tucked away inside my Library System Folder. As you may know, System files are shown greyed out and cannot be deleted by the user under the Mac operating system. However, using the “Space Lens” in my Clean My Mac App I was able to override this restriction and delete the folder. As this KEF Library System folder was clearly not part of the operating system I felt it safe to delete it. I have been running my computer for over a week now and everything seems to be working normally. I also use Qobuz Connect and Presto Music for streaming outside of Roon, which is becoming irrelevant for me, now that my music files are seldom used, as my favourite recordings have been found on line.
I’m using Funter-app for tasks like that.