Looks like in Android 10, "install from unknown sources" was changed from a global setting to a per-app permission. Apparently in order to install APKs now I need to whitelist each app that I'm trying to do this from. However, none of the apps I actually need to do this from (default system "Files" browser and Root Browser) even have this setting. Root Browser has a context menu to open with Package Installer but it doesn't work?
Do I need to get another third-party app just to install APKs from the filesystem? This is so lame. Thanks.
Edit: I am on a Pixel 3 running stock Android 10.0.