How do I move the clock to the right of the panel in Ubuntu GNOME?
In other words, I want the clock to be in the same place as in Ubuntu Unity 16.04.
You may use a GNOME shell extension called Frippery Move Clock to achieve this goal.
Also another extension called Unite
[...] makes a few layout tweaks to the top panel and removes window decorations to make it look like Ubuntu Unity Shell.
Moving the clock to the right is among the modifications it does.
Here is how I did it (on Ubuntu 18.04 LTS):
This would work. However, the side-effect (desired effect in my case) is that the 'Top panel' and the default Ubuntu 'dock' would merge together to form a single panel just like in the Windows OS.
You can use the Extend Panel Menu
which is found at https://extensions.gnome.org/extension/1201/extend-panel-menu/
as of Ubuntu 22 and Gnome 42, the Gnome extension "just perfection" lets you adjust the position of the clock to be left, middle or right.
https://extensions.gnome.org/extension/3843/just-perfection/
EDIT: (Off-topic: and if you want to tweak your clock, "Date Menu Formatter" is my choice) https://extensions.gnome.org/extension/4655/date-menu-formatter/