Actually, you listed two.
Zorin OS comes with Firefox - you merely suggested a modification to an existing install.
I agree with Synaptic. and both of these touch on:
It is realistic that the user can remove and replace at will. It is notable that "distro as is" influences the users - and that we on the forum can educate, discuss, give opinions or disagree.
@zenzen mentioned Gnome Tweaks. On this forum, we often end up suggesting the install in order to proceed with helping the user.
This one suggestion is worth some scrutiny - since Zorin OS Core does come with Gnome Control Center installed. Does Gnome Tweaks perform something that Control Center does not? Does it perform it better or in a way that is better for the end user?
There are good reasons to keep the Zorin OS .iso file as small as possible.
And the forum also has a thread specific to supplying suggestions to users for what to do after installing such as setting up zsh or alternative software.
Suggestions in this thread can help enhance the initial Zorin OS out of the box experience, not necessarily add to the Zorin OS install.