On 8 Jan 2019 18:47:02 GMT, Frank Slootweg
You can try MyPhoneExplorer [1] which is an Android/Windows combo which
can use an USB or WiFi connection. [snip]
My advice is to start with MyPhoneExplorer.
https://play.google.com/store/apps/details?id=com.fjsoft.myphoneexplorer.client

Many thanks for this tip, Frank. These two apps make synching
over Wi-Fi easy and fast. Both a phone client and a Windows
desktop client are required, the latter being available from
fosshub.com. The interface is a bit fiddly but once the tasks
are set up and saved, two clicks are all that is needed to update
a folder and its subfolders on the SD card. I spent a lot of
time looking for an easy and reliable way to do this and this is
it!