Here some info how to setup devmode Install Dev Mode Xbox Series S and X! Dev Mode Full Setup Tutorial & App Install Guide! - YouTube and here 1 on how to ftp (Xbox One) How To FTP Into Dev Mode For Free With FIlezilla - YouTube
Also check this https://gbatemp.net/threads/durango-ftp-an-ftp-server-for-xbox-one-and-series-consoles.580173/
There are many ways to transfer files and for everyone its more of a personal choice, if you google you can find pretty much all the info you need including how to unhide the hidden files etc.