I suppose I might identify as a "command-line-phobic user" so I gave the Startup Disk Creator a whirl on my Mint 21.3 system and a bit of poking and prodding to make it work. Not quite as eloquent and simple as the LE Creator but does the job. Nice to always have a different path to the same destination.
Both "gunzip" and "dd" are available in file manager's right click menu's for .gz and .img on Gnome. Your base OS GUI install got all the tools for image writing.