How can you stop apps from jacking around with the navigation buttons on Android 9?

This is a screenshot of my phone: The app in the screenshot has changed the foreground color of the navigation bar from what I set it to (white) to black, making it nearly invisible. It also added a booby-trap button on the left. Pressing and holding it makes the navigation bar disappear, and then it's tricky to get it back. I want to prevent apps from doing this. I don't want apps to be able to [change the navigation bar background color](https://stackoverflow.com/questions/27839105/android-lollipop-change-navigation-bar-color) , [change the navigation bar foreground color](https://stackoverflow.com/questions/56975703/how-to-change-navigation-bar-button-color) , remove the navigation bar, or add the booby-trap button. Apparently, it used to be possible to get control of the navigation bar back by installing an app called "Xposed". But now the only app with that name on Google Play is a social media app, and there's an "Xposed detector" that seems to be designed to detect the original app. I also hear that it used to be possible to deny an app permission to go to "full screen" mode, which would deny apps one way of removing the navigation bar. But there seems to be no such permission now, and there's [another way](https://stackoverflow.com/questions/9773006/how-do-you-remove-the-navigation-bar-on-android) to remove it. Is there any way left to stop app developers from making my phone unusable?