If you were to open the Software & Updates app and go to Additional Drivers, does the driver package you tested say it comes from Nvidia and it is "(proprietary, tested)"? If so, then your drivers should be fine. nvidia-driver-libs:i386 is 32-bit, so I don't know why you would need that installed unless DayZ is only compatible with 32-bit drivers for some reason. I have Steam installed on my Fedora install, and I don't have any 32-bit Nvidia drivers installed but everything works perfectly. That's a separate issue altogether, and I don't recommend running 32-bit drivers unless your system is 32-bit. Can you copy the "System Details" window in the About tab of the Settings app? It should have Hardware and Software information like the CPU, GPU, windowing system, etc. There are a few things that could cause issues that I might be able to glean from that.

I'm on Fedora, but since it's running Gnome it should theoretically look the same. You access the system details here:

Here's what mine looks like for reference:

System Details Report

Report details

• Date generated: 2024-01-10 07:58:06

Hardware Information:

• Hardware Model: ASUSTeK COMPUTER INC. ASUS TUF Dash F15 FX516PM_FX516PM
• Memory: 16.0 GiB
• Processor: 11th Gen Intel® Core™ i7-11370H × 8
• Graphics: Intel® Xe Graphics (TGL GT2)
• Graphics 1: NVIDIA GeForce RTX™ 3060 Laptop GPU
• Disk Capacity: 1.0 TB

Software Information:

• Firmware Version: FX516PM.329
• OS Name: Fedora Linux 39 (Workstation Edition)
• OS Build: (null)
• OS Type: 64-bit
• GNOME Version: 45.2
• Windowing System: X11
• Kernel Version: Linux 6.6.9-200.fc39.x86_64

To uninstall the steam snap, you should be able to open up a terminal and type the following:

sudo snap remove steam

And assuming that works, to install the native version of Steam (which should be what's installed anyway, but Canonical is pushing their proprietary snap BS that has never worked well), this should apparently work (I don't have an Ubuntu install to test on though):

sudo add-apt-repository multiverse
sudo apt update
sudo apt install steam

If it prompts you for anything, you can just confirm by typing "y". I'd recommend you check that it isn't installing the snap version, but I don't know how to guide you to do that, really. I haven't used a distro with the Aptitude package manager in over 5 years.

Of course, it probably isn't helpful, but I'd recommend avoiding vanilla Ubuntu if you aren't already too deeply invested. Linux Mint seems to be a common recommendation for new users and it's based off Ubuntu, but in all honesty I'd probably recommend Nobara (gaming focused and more user friendly version of Fedora). That way you don't get snaps shoved down your throat by Canonical, which break things constantly. Up to you if you want to install another OS though; in theory you shouldn't need to, and there should be a way to resolve these issues with your current install.

By the way, if you still have issues after the native Steam install and it gives you the same 32-bit driver warning, you should be able to resolve it with the following:

sudo dpkg --add-architecture i386
sudo apt update
sudo apt install nvidia-driver-libs:i386

That is of course assuming that the error message you pasted in another thread gave the correct package name, which is not a guarantee. It should have automatically been installed as a dependency to Steam if it was installed through apt though, so I don't feel like that will necessarily be a solution.