How do OS updates work in Linux? Is there a “Linux Update” program like what Windows has?

This is known as a package manager. The package manager (along with some default settings and preinstalled packages) is what makes each Linux distro different. For instance, Debian uses apt, Arch uses pacman, Gentoo uses emerge.

Each package manager uses a different way to upgrade software. For instance apt update refreshes the global list of available software and versions and apt upgrade finds differences between that list and what you have installed, and upgrades as needed.

There also snaps and flatpacks, but I don’t support the use of those.

How does digital security work on Linux? Is it more vulnerable due to being open source? Is there integrated antivirus software, or will I have to source that myself?

Yes and no. Open source allows attackers to find vulnerability in code, but also means more eyes are on that same code and able to fix those vulnerabilities.

Although permissions can largely be ignored on Windows, its critical to Linux. Its a little much to explain here, but a standard install is fairly secure because of permissions. The important thing to remember is to harden the root account (no remote login) and be very careful what you execute with the sudo command.

Many people [incorrectly] don’t use AV because historically Linux hasn’t been much of a target due to low adoption. The trifecta of software I use are ufw as a system-level firewall, fail2ban to block an attacker who tries to bruteforce entry and repeatedly fails, and ClamAV for AV.

Are GPU drivers reliable on Linux?

Yup

And also, what distro might be best for me?

I think Mint is currently the recommended distro for new users. It used to be Ubuntu, but canonical has been doing some very anti-community things lately.

I’m not a GUI expert, but last project I made with one, I used PyQt, and had a fairly good experience.

If you’re poor, you can’t really exploit the working class.

Of course you can. It’s called turning to crime. Most pimps, low level drug dealers, etc, aren’t rich.

OP isn’t referring to the package manager. They’re talking about Nginx Proxy Manager