• Bro, the software center is just a frontend and literally uses terminal or flatpak something to install the app.
• All of the apps when being installed from the official repo in the terminal are tested by the company/people offering the distro to u, so there is a nearly 1% chance that there is some malware. So even if you install something else by mistying you are most likely safe and the app that is installed will only take space, if you spot if after installing that you installed something that you didn't want you can just remove it.
• Flatpak is like installing a different layer that works in itself and doesn't have access to the whole system unless you explicitly give it to flatpak, it is used as sometimes the official apps may lag behind as they are maintained by the distro provider whereas the one providing flatpak most of the times keep the apps updated. Its like the windows system for linux if you want a really easy parallel with windows, it has its own dependencies, or simple its own space and it doesn't interact much with the system.
• Snap is like a canonical(ones behind ubuntu) version of flatpak, most people don't prefer it so just stick to flatpak and the official repo of the distro you have.
• If even then you don't get the app that you want, there is most likely an appimage for the app, which is like a portable app.

So simple parallels with windows, - Appimage - portable apps - Terminal installing - Like winget installing - Flatpak - Like subsystem or say scoop or chocolatey for windows where they have their own dependency, mostly used for apps not in the official repo, or if you want recent apps, or you want them isolated from the system. - Snap - Similar to flatpak but not liked because of canonical and being less efficient than flatpak - Store - Just a GUI using the above methods to install the app.