Out of bullshit (title), Android File Transfer is an MTP program that will help you as an intermediary between your favorite GNU / Linux distro and your Android devices connected to your computer. Although nothing is needed to make transfers between the two, with this tool based on a GUI it will be much easier for you and you will avoid some problems that you could have if you do not use it.
Android File Transfer allows you to mount Android devices as one more medium in your favorite Linux distribution. You just have to install it from your application manager. Once installed, you will have an app with a very intuitive graphical interface to transfer files between devices via USB reliably, safely and quickly. You just have to connect the Android device with the USB cable to your computer and let the software do its magic ...
This MTP client It is similar to the program available in macOS for this type of operation, with a very minimalist and simple interface. Among the functions that it allows, it has the ability to upload files to your Android device or download them to your PC, create new directories within the Android media, it also supports functions to cut and paste in the available media, you can delete files from the Android device and it has a dialog box where you can see the progress of the transfer.
You can also access both the internal memory of the Android device and the memory card if you have one. You can see all the main directories and navigate through them easily to locate what you are looking for or get where you want. You even have an option to manage albums in a very simple way. Without a doubt everything you need to manage your files and make copies or have everything at your disposal right on the device you want it ...
It is very good and as you say it is fast and reliable.
There is currently nothing comparable to Kdeconnect.
How do I install it on Fedora 30?