I have an old Android 9 (it's a Doogee Y9 Plus) device on which I would like to set Nova Launcher as the default home app, but there doesn't seem to be a way to set it through the device's settings. Every guide I could find states that you can change your default home app under Settings > Apps & notifications > Default apps > Home app, yet "Home app" isn't an option in Default apps on this device. When I navigate to either the device's default home app (which is called "Aurora Launcher") or Nova Launcher in the settings, "Home app" is there and is set to "Yes" and "No" respectively, but when I click on the option there, it takes me back to "Default apps" where the option doesn't exist. My question is: Is there a way to bypass this and forcefully change the launcher? Btw, if possible, I'd like to force uninstall or at least disable the native launcher after the change. I've been finding things about ADB, but since I've never used ADB before, I want to know if there are some other ways and if not, how to use ADB to fix it.

Is there a way to prevent settings on an Android phone from being accidentally changed? I am using an LG K30 running Android Pie. (Yes, I know it's a dinosaur)

And I don't mean the Screen Timeout or the actual phone lock. I have a Samsung Galaxy A8 running Android 9, and since I found out it hasn't been updated since 2018, AKA before OneUI, I decided to do it. But since that update, when I don't touch it for a bit, LESS than the ten minutes I set the screen timeout to be, the phone screen get dimmer and lock itself with a 'drag to unlock' message. It is annoying as I am using a third party program to help me grind in a mobile game, and what it feels like every five minutes I need to unlock the phone screen so that it can keep working. The screenlock must be new because it didn't happen before I updated it. I tried to see how to turn that off, but all I find is the Screen Timeout and the phone's actual lock, same for google searches. I can't find ANYTHING on this screen lock. Hell, even the 'Don't go to sleep while plugged it' dev setting doesn't stop it. Edit : Added a picture to show what I am talking about.

I see folders .com.taobao.dp and anycast with some files (about 500Kb) but Taobao and AnyCast applications were deleted a long time ago. So, is there a way/tool to find such files? (for example by application name or package?)