Thunderbird is the usual recommendation for an email client. So try that

That is why forks like librewolf exist.

git not installed in ubuntu based distro was the shock for me.

Flatpak and snap don't use system theme unless you tell it.

https://itsfoss.com/flatpak-app-apply-theme/

https://www.omgubuntu.co.uk/2020/06/change-snap-app-theme/amp

Endeavouros would be recommended if you like arch , if you want an rolling relase you could try Opensuse Tumbleweed, or fairly updated but stable then Fedora.

Well understandable , since thats the default look. But KDE is one of the most customizable DE, you could make it look like anything you want.

It looks like it runs in wine. https://www.reddit.com/r/scrivener/comments/102pvtk/scrivener_on_linux_abandoned/

Mint is easiest for old windows users.

You can change the kernel if you want through update manager.Linux mint doesnt always follow with ubuntu.

Opensource is a more used term compared to foss. So popularity wise it was chosen is my guess.

It would since the app is a modified version of discord.

Roblox is working on it there is unofficial way using grapejuice coming soon.

Have you tried distrobox ? That would sound more reasonable.

It did do it on old versions now it doesn't.

Fork of android firefox

First are you using the latest arch iso then get that then check if there are updates for archinstall and is windows fully shutdown i.e do you have fast startup enabled or not if so disable it .

Before asking maybe check the archwiki since most problems usually have solution there.

https://wiki.archlinux.org/title/Discord

Which nvidia card and what driver version.

If you are using defaults in gnome it's fine, but custom themes don't work.

If you like an online one , you can use photopea.

In panel settings , switch off the automatic size for icons that would fix it for you.