I ran thru your tutorial - I think it worked ok but here were some errors that I couldn’t easily copy/paste (and they were long).
I think the driver was installed ok (although I’m not sure Unity is behaving any better)- how can I check which driver is installed?
Normally it shouldn’t produce any errors, but let’s check nonetheless.
From your menu, type in nvidia-settings - if the driver was installed correctly, it will appear and show you which GFX card you have with all the extensions (and versions) installed.
I assume you mean in the console…
ERROR: NVIDIA driver is not loaded
ERROR: Unable to load info from any available system
Here we go again.
There were 2 different lines starting with ‘linux /boot/vmlinuz’ (not kernel), so I entered a 3 (after a space) at the end of both of them. They both already had a 3 (something like ‘settings3’ - can’t remember)
I’ll do another clean linux install…
But I’ll need you here if I do the Nvidia setup again, so I can tell you what’s happening =)
We’ll have to setup the timezones then! Yesterday I wasn’t on the forums as I’m working non-stop to finish a video for our LMS platform. 
What’s LMS?
If you’re around this afternoon / evening (your time) I’ll do the clean install now
Did a clean Manjaro install so can do Nvidia drivers any time that works for you.
I have the downloaded Nvidia file.
I’m 17 hours ahead of you, so if you want to know what the future looks like, I’m your man 
LMS is the Learning Management System. It’s a set of courses we have for $20 subscription, where we add courses every week (and has weekly live Workshops).
You’re in the future indeed! 
I’ll be around today, so we can get through with it.
First, I would recommend you open up a terminal and run:
sudo pacman -S dkms
This will set the pre-requisite app to install the driver module.
Cool!
Ok so I’ve booted and added a 3 to the end of the line in the GRUB boot parameters.
Interestingly, only one line this time… so far so good
So during the process I have a message:
WARNING: Unable to determine the path to install the libglvnd EGL vendor library config files. Check that you have pkg-config and the libglvnd development libraries installed, or specify a path with --glvnd-egl-config-path.
The only option is ‘OK’ so I chose that…
ERROR: Failed to run ‘/usr/bin/dkms build -m nvidia -v 470.74 -k 5.13.19-2-MANJARO’: Error! Your kernel headers for kernel 5.13.19-2-MANJARO cannot be found at /usr/lib/modules/5.13.19-2-MANJARO/build or /usr/lib/modules/5.13.19.2-MANJARO/source.
You can use the --kernelsourcedir option to tell DKMS where it’s located.
ERROR: Failed to install the kernel module through DKMS. No kernel module was installed: please try installing again without DKMS, or check the DKMS logs for more information.
ERROR: Installation has failed. Please see the file ‘/var/log/nvidia-installer-log’ for details. You may find suggestions on fixing installation problems in the README available on the Linux driver download page at www.nvidia.com.
What you will need - since it’s not there - is the Linux Headers, that contain the source code.
Type in (terminal, root shell, anywhere you find yourself in ):
sudo pacman -S linux-headers
Then you can retry the install.
Did that - same errors. 
Did you install DKMS?
Yes! In fact the error message suggests trying without it
Installation without DKMS is still possible. However, every time you get a Kernel update, you’ll need to reinstall the driver. That’s going to be a pain.
Now that I’m thinking about it. Have you tried POP!_OS? It has a lower Kernel (5.11), but you can upgrade it to 5.13. Its installation ISO comes with the Nvidia drivers embedded and pre-installed.
Looks good, so gave it a try.
All installs ok, finds WiFi (still no Bluetooth)… BUT…
it freezes up after a few seconds of use - I’ve had to reboot about 6 times. Each time it freezes I’m doing something different.
Unless you’ve got any idea why this might be, I’ve had enough.