I understand that Deja Dup uses Duplicity. I am using Deja Dup 42.7 (flatpak) and I can find these references to duplicity:
find . -iname duplicity ./.local/share/flatpak/app/org.gnome.DejaDup/x86_64/stable/2002eb71ae52f806113aba497608a65d9ca9db6f6321cb16b643065ee6846773/files/lib/python3.8/site-packages/duplicity ./.local/share/flatpak/app/org.gnome.DejaDup/x86_64/stable/2002eb71ae52f806113aba497608a65d9ca9db6f6321cb16b643065ee6846773/files/bin/duplicity
However, I cannot run Duplicity from the command line. Is there a way to do that other than installing Duplicity separately? I am concerned about having two, potentially conflicting, instances of Duplicity – one of Duplicity itself and the other from Deja Dup. Is that concern unnecessary?