AdbFileManager
Alternative for the MTP which is slow AF. It uses adb protocol to copy files which is lot faster
To use this app, you must have enabled USB Debugging in android developer settings.
After enabling it, just go to the directory from where you want to copy from/where to copy, select the file(s) and hit the arrow to the correct copy direction
Note: to go up a directory, double click the file header!
Note2: Its made in C# and Windows Forms. To put it on Linux/Mac I would completely have to rewrite it, so no Linux/Mac version