So I’d suggest, unless you really really need some obscure feature, Calibre+Kindle is nowadays perfectly fine, and maybe you shouldn’t risk bricking your device.
Uhm… Well about that… You will not be able to transfer books onto you kindle via USB in about a week. Amazon is going to remove that feature from all Kindles next week. The only way to do that may be through the method you described. But how long will they offer that, if they say they are removing the USB feature because of piracy? You cannot pirate books onto your kindle, when you cannot transfer books from outside of Amazon onto it. (Also this is a nice reason for them to block you from buying books anywhere else than on Amazon, of course)
https://www.theverge.com/news/612898/amazon-removing-kindle-book-download-transfer-usb
Somewhat, I read a German news article that explicitly warned that USB transfer will be blocked. I just searched for an English article to post here afterwards, but I didn’t read it. So… yeah, „lost in translation“