I have retried with https://cdimage.debian.org/cdimage/weekly-builds/amd64/iso-dvd/debian-testing-amd64-DVD-1.iso and hit the same issue. Image was written with dd and definitely contains firmware-iwlwifi_20230210-1_all.deb
I'd also like to note https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1031696, from the creator of Rufus.
