I have never seen such a stubborn program to get rid of .... I have deleted it from my Software Store and I think from my laptop but every time Software Updates updates there it is again trying to install language packs and what not ..... I tried to ignore these updates but there they are next time ....
I have no need for this browser and probably never will ..... so please how can I finally shot this wounded creature .... 
have you checked to see where it is installed? Snap flatpak appimage apt?
I never installed it it was already installed when I started up Zorin long ago .... I know it isn't on Snap cause Snap is not installed .... didn't see it in Flatpak ....
try
sudo apt purge firefox -f
Thank you sir that seemed to work .... will have to see if it rears it's ugly head in the future .....
mike@mike-ROG-Strix-G731GT-G731GT:~$ sudo apt purge firefox -f
[sudo] password for mike:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
fonts-lyx
Use 'sudo apt autoremove' to remove it.
The following packages will be REMOVED:
firefox*
0 upgraded, 0 newly installed, 1 to remove and 5 not upgraded.
After this operation, 238 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 272585 files and directories currently installed.)
Removing firefox (106.0.2+build1-0ubuntu0.20.04.1) ...
Processing triggers for mime-support (3.64ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu3) ...
(Reading database ... 272498 files and directories currently installed.)
Purging configuration files for firefox (106.0.2+build1-0ubuntu0.20.04.1) ...
mike@mike-ROG-Strix-G731GT-G731GT:~$
remove just uninstalls the app, and purge removes the app files configs and user preferences. its more dangerous but does a better job, use sparingly 
Thanks I'll make a physical note of that command ..... but use it as a last resort .... I did a restart just now and all is well ..... thanks again ....
That has been a thorn in my side for a very long time ..... but as I am now very closely scrutinizing what Zorin updates it makes a difference ..... before I would just let Updates update everything on it's agenda .... but not any more .....
I even take a screenshot of what is being updated and saving a copy in my Pictures Folder so if things go belly-up I can see where the problem lies rather than try to remember how far back the problem occurred .....
Better safe than sorry ..... 
I removed Blanket for the very reason it auto-updates without warning. I actually liked Blanket but the auto-update just sat wrong with me.
I use Blanket now ..... I love the bird sounds ..... I leave on all day just something so relaxing to me like being out in the woods on a nice warm spring day ..... now if I could just find a nice pine scented room freshener I could curl up on the floor and go to sleep ....
By the way I never noticed it downloading by itself and it hasn't come up in the Zorin Updates ..... at least not that I have noticed and I am now checking this updates like a fat boy checks his donuts .... and don't ask me how I know that ....
Let me guess:
Because you are a doughnut.
Language packs are usually separate packages. It is a pity other applications don't follow LibreOffice that after you chooae your language all other languages get removed. Or it is how Devuan put it together at install thinking about it.
My doctor instructed me to lose weight so donuts are "verboten".
I would not have known Blanket was updating but for the fact it would provide a popup stating so. This was always right after the first boot of the day. The popup only lasted a few seconds.
I generally dislike any sort of "auto" action, be it updates, renewals, etc.
It's good to have a backup browser, especially for banking. Even Chrome gets funky sometimes.
Well it is back ..... at least the language pack is back ..... how to get rid of it ..... tired of hitting the Remind Me Later button .....
I agree it is a royal PITA ..... especially as it is under Security .... 
Just did an apt update and got this ..... notice the Fire Fox entree .... the very first one .....
mike@mike-ROG-Strix-G731GT-G731GT:~$ apt list --upgradable
Listing... Done
firefox-locale-en/focal-security,focal-security 106.0.5+build1-0ubuntu0.20.04.1 amd64 [upgradable from: 106.0.2+build1-0ubuntu0.20.04.1]
gnome-software-common/focal,focal 3.36.1-0ubuntu0.20.04.1+zorin1+old1 all [upgradable from: 3.36.1-0ubuntu0.20.04.0+zorin1]
gnome-software-plugin-flatpak/focal 3.36.1-0ubuntu0.20.04.1+zorin1+old1 amd64 [upgradable from: 3.36.1-0ubuntu0.20.04.0+zorin1]
gnome-software-plugin-snap/focal 3.36.1-0ubuntu0.20.04.1+zorin1+old1 amd64 [upgradable from: 3.36.1-0ubuntu0.20.04.0+zorin1]
gnome-software/focal 3.36.1-0ubuntu0.20.04.1+zorin1+old1 amd64 [upgradable from: 3.36.1-0ubuntu0.20.04.0+zorin1]
mike@mike-ROG-Strix-G731GT-G731GT:~$
Try
sudo apt remove --purge remove 'firefox-locale-*'
Note, selecting 'firefox-locale-ast' for glob 'firefox-locale-'
Note, selecting 'firefox-locale-cak' for glob 'firefox-locale-'
Note, selecting 'firefox-locale-csb' for glob 'firefox-locale-*'
E: Unable to locate package remove
mike@mike-ROG-Strix-G731GT-G731GT:~$
I hate it when I do that...
sudo apt remove --purge 'firefox-locale-*'
Use 'sudo apt autoremove' to remove it.
The following packages will be REMOVED:
firefox-locale-en*
0 upgraded, 0 newly installed, 1 to remove and 4 not upgraded.
After this operation, 1,201 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 272492 files and directories currently installed.)
Removing firefox-locale-en (106.0.2+build1-0ubuntu0.20.04.1) ...
mike@mike-ROG-Strix-G731GT-G731GT:~$ sudo apt autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
fonts-lyx
0 upgraded, 0 newly installed, 1 to remove and 4 not upgraded.
After this operation, 350 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 272485 files and directories currently installed.)
Removing fonts-lyx (2.3.4.2-2) ...
dpkg: warning: while removing fonts-lyx, directory '/usr/share/fonts/truetype/lyx' not
empty so not removed
Processing triggers for fontconfig (2.13.1-2ubuntu3) ...
mike@mike-ROG-Strix-G731GT-G731GT:~$
