@paequ2@lemmy.today "Emacs" will launch a new instance of Emacs, while "Emacs (Client)" will connect to an already running Emacs Server – unless Emacs takes a long time to start up you may not notice a difference.
Doom and Spacemacs are predefined configurations for Emacs that include many additional packages and custom settings, all of which you could manually add to your own Emacs configuration if you had the time and patience. They both include a range of opinionated decisions about what packages to include and how Emacs should look and feel, which may or may not suit you. I don't use either of them, but if you're coming from Vim you might find them interesting because they provide a similar modal editing experience.
I've only used the GUI interface, and I think it has some UI features that aren't available in the TUI interface, but you should be able to use both with (mostly? entirely?) the same configuration.
There are various ways to run terminal/shell sessions from within Emacs, and to run shell commands and capture their output. So while I almost exclusively use the command line, I do it all from within the Emacs GUI.
If you happen to use
git, you might consider trying magit, an Emacs interface for usinggitthat many people find vastly preferable to usinggitdirectly.