Or use a little USB-Stick (one side USB-a and one side USB-c) for your backups.
Example (I chose the cheapest available)
You can set your smartphone backup program (Seedvault) to automatically run the backup every time you connect the stick. Very convenient and quick.
And if you want to backup the data additionally on your computer, the USB-A works fine for plugging in the USB-stick to the computer and saving a second copy onto there.