Conrats on the Note 9 move - wish you the best of luck with it. It's an incredible device, really.
Now- you've not had a Samsung since the Slll, but have you been on any android device over the last several years, or just Apple? (Not counting the laptops/other tech). If not, that's quite a big move from one ecosystem to another. Some people have no issues with it, others do. Note 9 has so much to offer, you are bound to be able to create its setup to your liking though

Customization abilities are seemingly endless.
You'll find custom launchers a great tool, if you want to go that route. You can customize your home screen in many ways such as iconsize, background color/photos, icon design, what various motions do (Swipe up, swipe down, etc). I use Nova Launcher, have a custom theme, and custom icons with a size to my liking. Here's a couple of screen shots to show you.
You will love it - I can't imagine you wouldn't.
Not sure with Apple, but with the Note 9, you can pick any bluetooth device to pair it to - no matter the Mfg (Only thing I'm not sure of is pairing Apple Bluetooth to Samsung phones). I have two different bluetooth keyboards, a third different mfg bluetooth mouse, and have used a few different smart watches.

