Is there any method similar to sudo dnf update to update all Python packages in Fedora?
Do I understand you correctly that you want to update only python packages instead of all? If so, dnf upgrade 'python*' should do the trick.
Does this command update all the packages installed via pip such as tensorflow?
Ah, sorry, no. Dnf only knows about rpm packages installed via dnf/Gnome Software/dnfdragora etc., so dnf upgrade will only update python things you got from Fedora’s repositories, not those installed via pip.
I don’t use pip myself but I found this link: