Some more context would help: Massimo's image or plain Raspbian/Raspberry Pi OS?
Anyways, that link seems broken, but if you remove the trailing "/p", it gives a directory listing.
I don't know enough about Debian's repo organization to explain what's wrong here...
Raspberry Pi OS should be able to mount USB sticks, I use several variants of it (stock RPi OS, Patchbox OS, etc.) and all can do that
On QLC image, it may be easier to use ssh/scp and transfer your image from a PC. See the QLC+_RaspberryPi_Buster_Guide, chapter 5.3
Or put the SD card in your main PC and copy the image over to somewhere in the RPi's user folder.