Thanks, yeah i already have PopOS running on my VM to get used to Linux in general.
I also heard about Arch (kinda advanced?).
If you can read, follow instructions and are willing to put in the time Arch is not as hard and elite as Reddit threads make it seem. The Arch way installation is installing it through the Arch installation guide but they have a python installation script now days. If you want to go with Arch
EndeavorOS is just as good but you get to install it with a gui installer. However Arch and Arch based are rolling release distributions so more likely that something will break and when it does you will have to know how to fix it yourself.
Gentoo is different but a manual install as well and you will have lots of compile time since it's a source based distribution, I would recommend going for a binary distribution unless you have a specific reason you want to use a source based distribution.
It's just 2 klicks to google this stuff but as a complete beginner what does that mean? will i be unable to install certain programs or will there be limitations in any way? what if i want o install another program in the future? what about program updates? why are some drivers not up to date? ...
With most distributions you have a gui application installed from where you can install/update/remove/search for software and some Desktop Environments have Flatpaks or Snaps integrated into that so you won't actually need to know the package manager. If you want to use the command-line to manage your software then you will have to learn the basic commands of the package manager but once you know one it doesn't take much effort to learn another.
Most of my Linux years I work with apt-get/apt-cache and yum, later something new came called apt but apt is a wrapper of the original commands I won't go into detail for now. A few years ago I decided to install Arch for the first time and I had never worked with pacman, it ook me a few days to get used to but those package manager basically have the same command-line type principals of how they are setup. The following link will give you an idea.
wiki.archlinux.org
Flatpaks, Snaps and AppImages are just new different ways of package applications which should technically work on all distributions, I don't know all the technical details. An AppImage is a file you download somewhere make executable and then run, downside of this it doesn't really have integration into your application/start menu. Snaps are made by Canonical and the back-end is proprietary which people don't like and for every snap you install a loop-back device is created which people also dislike and from my experience for some applications Snaps seems slower than a native package(rpm, deb, etc.) Under Ubuntu you can manage snaps from the software center as well and the default use is to use snap instead of Deb. If you want to install snaps from the command-line the basic package manger format is the same as with the normal package manager.
native packages: apt install/remove firefox
snap packages: snap install/remove firefox
Flatpak is comparable to Snaps but just different technology and it has limitations compared to snap since snap can also be used for command-line applications, Flatpaks are only for gui applications. Snaps and Flatpak are both sandbox applications although I don't know the details about that. Some graphical environments have the software center integrated Flatpaks too so you can install them from a gui, as for installing Flatpaks from the command-line you will have to add a source if that hasn't been added, in most cases that will be
Flathub.
Find and install hundreds of apps and games for Linux. Enjoy Firefox, Telegram, RetroArch, GIMP and many more!
flathub.org
Then same as Snaps but just a bit different:
native packages: apt install firefox
flatpak packages: flatpak install org.mozilla.firefox
The downside of Flatpaks is the long names of the application but I think they are working on a solution for that. Flatpaks and Snaps have start/menu integration. I don't know everything about AppImages, Snaps and Flatpaks so I will probably have missed some things but I was just trying to explain the general idea. I personally prefer Flatpaks and I just those to run applications that aren't opensource so they are sandboxed.
You can also install applications from source but that would give you a headache being a beginner. Also some distributions have a bigger software collections than. So there will be some software that you can't find in the default repos one distribution but you can find in the default repos of another. So AppImages, Snaps and Flatpaks gives you the option to have more available for applications on your distribution if it isn't in the default repos. Lastly to answer one of your question AppImages, Snaps and Flatpaks are usable across all the different Linux distributions.
Oh yeah I forgot to mention you also have third-party repos available for most distributions. With Ubuntu those are called ppa's, with Fedora nothing special just another yum repo with a source, Arch also has third party but not really need and with Arch and Arch based distributions you have the Arch User Repository(AUR). When you you have PKGBUILDS which you can use to build software which isn't in the default repos.
About driver updates most of the drivers are in the Linux kernel and you get a kernel update and reboot your system you will have activated driver updates if those were added in the new kernel. Unless you use an Nvidia graphics card then you will have to install an Nvidia package from the defautl repos. Distributions that are more beginner friendly like Ubuntu, Mint and PopOS have a graphical driver manager that help you with that. AMD graphics card use opensource drivers that use opensource drivers that are in the kernel and those work with mesa which is installed by default. For some applications the opensource drivers aren't enough and then you will have to install the AMD proprietary drivers.
Also something useful to know you have different graphics environments, everyone has their preference so you will want try out a few which you like. There are also different flavors of distributions when it comes to Graphical Environments(in short they are called DE's) Here's a list from the Archwiki just to give you an idea.
wiki.archlinux.org
Cinnamon, Gnome, and KDE Plasma are the more well known ones but you have other as well. Once you understand Linux there are only minor differences between the distributions and the most differences will be in the different DE's.
I can't answer or try out your issues with UE5 because I don't use it and I don't feel like spending time with it if I'm not going to use it. The other option might be to run UE5 in a Windows vm on top of your Linux installation but I don't know how much cpu or graphics power UE5 requires.
As a side note I am not good at explaining things but I hope I did a good enough job for you to get a basic understanding of the questions you had and the confusion you ran into. Others here are better at explaining then me and different people are better in different areas here, so if you are stuck on something feel free just to create a topic here and plenty of people who are willing to help if you if you put some effort into your topic.