How to uninstall Google/Samsung apps properly? I have a Galaxy A5 2016 and I would like to remove all Google apps for the sake of privacy. I have a rooted phone and it's running Samsung firmware.

I've tried simply uninstalling the apps with an uninstaller app, but when I had removed Google Play Store and Google Play Services some features such as WiFi and 4G stopped working. I know I can disable the apps in settings, but that doesn't achieve the goal of privacy that I have in mind, as the apps still continue to run in the background.

Is there a way to remove these Google apps and keep the phone in working condition?
Install a custom ROM from the relevant XDA forum https://forum.xda-developers.com/samsung-a-series. Make sure you choose one that doesn't have GApps installed by default e.g. lite edition of this one. Then you can install microG (open source reimplementation) selectively as you require for apps that do need Play Services. 

I'm sure you could wrestle around with adb etc to get it working with your current setup but probably easier to start with a clean slate and make sure nothing is left behind if you are concerned about privacy.