In general apps that are pre-installed cannot be uninstalled. But you can generally make everything default to one app, and you can usually "disable" alternatives if you can't remove them (which has the same effect: pre-installed apps live in a different partition so don't take up space that your own apps could use, so if they disappear from the app drawer and won't run then as if they are not installed, the only difference is that you can find them in the app manager menu). You can always uninstall any app you installed yourself.
I personally use very few built-in apps, as there's usually a better alternative in the play store. But then I either disable built in apps which I don't want, or hide them from the app drawer (a third party "launcher" - the app that provides the desktop and app drawer - will allow you to do this), so I rarely see them. Unlike an iPhone, which puts all apps on the desktop, with Android you have more options for hiding away unwanted or rarely-used stuff.
There are occasional exceptions to the "you can make everything default to one". For example, the camera app will let you view the photo you just took, but this uses the Gallery app, and you may not be able to choose which gallery app the camera app uses (with some manufacturers their camera app may be hard-coded to use their gallery app). If you use the manufacturer's gallery app anyway you may not notice this as a problem, or it may be that the S7E does let you change it, but I mention this as an exception that I have encountered. Usually though if you have 2 apps that can open a particular type of file, when you try to open one it will ask you which app you wish to use and whether you want to do so just once or always. If you select always then it won't ask you again.
I don't have an S7 Edge, so cannot tell you what apps it includes. And if you are buying it through a carrier they may add their own apps too, so even if I had one my answer might not be complete/correct. And because I've never even used an S7E (too big for my tastes) I can't comment on its scrolling (though I'd expect the Pixel to be better in that respect - I could name a couple of others too, but you didn't want more options). My advice would be to go and play with one before laying out money on it and see how it feels to you, because only you can say what you would find OK.
If you make the change though you will find things "complicated" at first, just because some things are different and you are used to the iOS way of doing everything. When I use iPhones I find them strangely complicated and awkward for some tasks, which is in part because I'm used to doing things a certain way and can do them more quickly with Android.