Unfortunately, for some phones, bloatware will inevitably be installed on the phone if third-party tools are used.
Usually, rooting would involve this:
Flash a custom recovery -> use said recovery to flash a zip -> profit
Of course, a custom recovery won't introduce bloatware in 99.999% of cases. The zip file, provided you use one that is from a very reliable author, is also bloat-free.
Now, some phones go through this process:
Install a tool, usually in an APK form -> Press a button -> profit
This is where things can go many ways. Your phone's fate depends solely on the authors of the tool.
Some tools, such as towelroot, probably do not care about profits and as such simply does their job (rooting the phone) and nothing else. Unfortunately, other tools (like KingRoot/KingoRoot) do care about profits.
To answer your question, unless you know how to deal with low-level stuff instead of using third-party tools, bloatware is inevitable.
Since you already acquired root, you can probably:
- Install SuperSU/Superuser from the Play Store
- Install a root-enabled app manager
- Disable internet connection
- Remove KingRoot/KingoRoot/whatever-Rooting-App-You-Used and everything they installed.
- Restart phone, and deny all unfamiliar
- Since some bloatware have monitoring services that monitor their bloat and reinstall if necessary (ala persistent Android malware)
- Also remove said unfamiliar apps using #2. Rinse and repeat.
- This does not guarantee a clean system. There may be other unwanted stuff lingering about.
- Some SU apps (e.g. Superuser) have this option to allow all
su requests during boot. Disable this while you're sanitizing your phone. Do not enable unless you know you need to.