The app I use to sync, Musicbee, doesn't work on Linux, so I have to use Wine, which for stupid reasons prevents me from syncing wirelessly. Just syncing the files isn't the problem. Syncing the metadata (number of times a song has been played, favourites) is the problem, and just dragging-and-dropping the the files onto my phone doesn't solve for this.

If I could do it wirelessly, I would, but I've never found it to be reliable in the first place the few times I've used it before (times may have changed).