I found an article where Spap, Flatpak, and Appimage are compared. The author then compares them to eopkg (yes, eopkg!):
https://verummeum.com/portable-package-formats/
Some interesting conclusions, in case you don't want to read the article:
AppImages are the smallest in size in all our test cases
Snap packages seem to be more resource heavy compared to the other package formats. The resource usage of Flatpak and AppImage packages were very similar in all test cases.
My opinion. I have used the Zoom flatpak and it worked fine. I tend to avoid snaps, I heard some problems about them, but don't want to say anything without a source. Appimages seem OK, but you cannot update them, you just download the newer version.