I just switched from Kiwi Browser to Bromite and and Bromite SystemWebView, now I'm wondering if I still need to keep AdAway around.
Maybe you can find the time and comment here or in my discussion on reddit (https://www.reddit.com/r/fossdroid/comments/d88ljd/does_adaw...)?
For most users Bromite itself will be sufficient; I see you are also using the SystemWebView, so I don't think you need to run AdAway, you can save CPU usage and battery without it. I suggest you try disabling/uninstalling it, there should be no difference in your experience.
I currently have only one app that shows ads (Easy Currency), and it still does it despite of AdAway being up and running, so I assume AdAway is not of much use for blocking ads in apps because they are fed in a different way.
The native Chromium adblock engine is the subresource filter and works with the modern NetworkService; this has already been answered on XDA, but basically it is more efficient and has a bit more features (CSS filtering).