Edit: realized you meant in the sense of hot swapping flavors after I typed out a whole explanation lol. Should start recommending niche distros and collect package managers like trading cards lol.

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yum = dnf, dnf is just the newer version which was rewritten several times.

apt is a weird attempt to “upgrade” apt-get with better user interface without messing with the compatibility of apt-get used by scripts and whatnot.

Both of these are dependency handling package managers which do all the magic of installing required subpackges when you want something.

rpm is the underlying system package manager which deals with the actual task of installing, removing, and generating packages in the .rpm format. It is analogous to Debian’s dpkg which uses the .deb format. It’s usually not used by the end user unless you need to play with a package directly like with a .rpm or .deb file.

Hence why some distros (or people) have their own dependency package manager, like zypper on OpenSUSE (rpm) or Aptitude on Debian (deb).

Although I think Aptitude might just be a fancy wrapper for apt lol.