Weird how one answer gets more upvotes

I have Mull installed 129.0.2 https://f-droid.org/repo/us.spotco.fennec_dos_21290220.apk

Should I uninstall?

Is there any way to export bookmarks from mull, so that I can uninstall it?

I am gonna simplify it. This contains a lot of generalisation.

A distro or distribution is like Windows or macOS. When you want to install applications you mainly look for applications (they are generally called packages in linux) that are built for these distros. Major ones are Debian (Ubuntu comes under this), Fedora and Arch. Here the Debian/Ubuntu is the most user friendly with lots of guides and forums to help you get going. Most applications that has a Linux version will support Ubuntu. Major advantage of Debian is that, its stable. Because of this, core files that a system needs to run will be thoroughly tested and will not break. If you are testing the waters, you should go with distributions like Debian 12, Ubuntu 24 or 22.

Okay, coming to Desktop Environments, for now you only need to know about two, KDE, & Gnome. They are the GUI that you interact with. They come with basic GUI applications like a file manager, Terminal Emulators, etc. If you like window 10 style, you can go with KDE and Gnome is a little different, but its the default option in Ubuntu I think. You can install any DEs on any distributions but may require some know how. So DEs are for basic utility and Look and Feel.

Image: Gnome on Debian 12
Image: KDE on Debian 12

You gotta stop putting things in your mouth.

Fujitsu made laptops?

Major DEs are almost safe.

Go to flathub and check the permission of the application that you want to install. Normally they won’t have access to root directory, but could access your home dir. If they had any malicious intent, they could mess with your personal files.
I think there is another application that can restrict the permission scope on flathub itself.

Full signal with slow speeds? How about that?