Hopefully it tells you if you are installing a deb or a flatpak app more clearly. I can only tell by the size in the current pop shop.
On Neo store, f-droid front end, in the settings there is an option to auto update all apps. Also has a one click button to update all apps if you don't want to auto update.
They will add it to f-droid once they get all of their 1.0 tasks done.
Not a game developer but I have a hunch that its for displaying videos within the game. Like a cut scene.
In a high level, you are correct that Ubuntu is a standalone OS like Fedora. Other distributions have used the background packages that make up Ubuntu to form their own OS with changes here and there. It is similar to how Ubuntu is built on top of Debian.
Sure others can explain this better.
Since you are more familiar with Windows, Linux Mint may be a good start. Can also try PopOS for a different desktop layout, more similar to Mac. These are Ubuntu based systems. Can also give Fedora a try, but may require a bit more of a learning curve. There is also Nobora for a more gaming oriented version of fedora. Try out the live previews before installing to make sure your system works properly.
Not sure if this is something that will help but the site Linux Journey might help you learn how to use and understand Linux more. This is more the core stuff and command line oriented.
For easier transition, start using programs that are available on both systems so you don't have to jump in cold turkey, if that may be too much. When looking for programs on Linux, always use the provided store first to search. Since you are a programmer, you are aware that there will always be multiple ways to do the same thing, web searching is your friend, just make sure you are searching for the right based system, in the examples above, Fedora or Ubuntu. For programming you are going to enjoy Linux more than windows :).
Remember this is a journey and will take time. Have fun!
From my experience, its overall good. Its basically stock android, meaning no google smart features and apps by default, with more control over apps and google services. But for caution, some apps may break. You will have to mess around with the app settings to fix them. Also some apps will not work such as the google wallet app due to the OS not being acknowledged as official by google.
In short, its a more security focused OS that may require more involvement in configuration.
Dead space. The remake was just as good as the original but with updated graphics and mechanics.
No it's a local application like Libre. Can also be ran in the cloud.
Red dead redemption 2 has a really good story. Gameplay is pretty immersive and lots to explore.
God of war have a really good story and gameplay is overall fun.
Ni no Kuni II I found to be an interesting story. Gameplay was fun overall.
Ori, both games, has a good story to tell. Overall good platformer
Hollow knight is a fun platformer and overall story is good. Similar but not as good, death's door.
Death stranding has an interesting story but kind of strange. Gameplay is OK but can get a bit repetitive at times.
Spider-Man, overall fun. Story is unique.
Ghost of tsushima, good story and gameplay. Visually lovely.
Cyberpunk 2077 I found immersive, story wasn't bad but might not be for everyone.
Balance on random things when I'm walking. Also imagine racing my cart sometimes when I'm at the store.
Currently Guild Wars 2, I suppose.