@agnostic-apollo could you briefly list what other improvements that should/could be done with termux-shared? I suppose all logging should be moved over to termux-shared's logger functions for example

Ah, so you finally got around to this ;)

1. Replace both com.termux.sharedfiles.READ with ${TERMUX_PACKAGE_NAME}.sharedfiles.READ in AndroidManifest.xml. Make sure to validate correct expansion in built apk, you can drag and drop apk into android studio to check.
2. Remove all com.termux.api prefixes and use dot notation in AndroidManifest.xml.
3. I have implemented consistent base theming in termux-app locally, which is/will be used by all components Activity/Dialogs and plugins, which will automatically change on dark mode changes. The use-black-ui bool property has been deprecated and automatically replaced with night-mode string property to be consistent with android conventions. So DialogActivity would either need to use the base theme or use new property for which a helper function is provided. Dialogs itself may be replaced too, since implemented too.
4. Just like termux-widget and other plugins, termux-api needs to add a launcher activity to be exempted from OEM killers and also to reduce bug reports of users not having uninstalled all termux apps and trying to change install sources. Check Sometimes the widget stops to work termux-widget#56. The ".activities.TermuxWidgetActivity" theme has changed too locally and also requires toolbar and night mode calls. I guess I can this one myself when I push termux-app changes.
5. You need to use Logger throughout. The TermuxApiReceiver.onReceive() must have following.

TermuxApiApplication.setLogLevel(context, false);
Logger.logDebug(LOG_TAG, "Intent Received:\n" + IntentUtils.getIntentString(intent));

6. Each class must have its own LOG_TAG. Classes that have services or receivers instead of direct function runs like StorageActivity must have log entries when command is received/started or onActivityResult with logVerbose. This is important since android or more specifically OEM restrictions may not start them, and we should know if that happens. If we see TermuxApiReceiver log statement but not the command received one, we would know something unexpected happened and can investigate further.
7. The TermuxApiApplication class must be defined in com.termux.api package and added to AndroidManifest.xml.

<application
        android:name=".TermuxApiApplication"

package com.termux.api;

import android.app.Application;
import android.content.Context;

import com.termux.shared.logger.Logger;
import com.termux.shared.termux.TermuxConstants;
import com.termux.shared.termux.crash.TermuxCrashUtils;
import com.termux.shared.termux.settings.preferences.TermuxApiAppSharedPreferences;


public class TermuxApiApplication extends Application {

    public void onCreate() {
        super.onCreate();

        // Set crash handler for the app
        TermuxCrashUtils.setCrashHandler(this);

        // Set log config for the app
        setLogConfig(getApplicationContext(), true);

        Logger.logDebug("Starting Application");
    }

    public static void setLogConfig(Context context, boolean commitToFile) {
        Logger.setDefaultLogTag(TermuxConstants.TERMUX_API_APP_NAME);

        // Load the log level from shared preferences and set it to the {@link Logger.CURRENT_LOG_LEVEL}
        TermuxApiAppSharedPreferences preferences = TermuxApiAppSharedPreferences.build(context);
        if (preferences == null) return;
        preferences.setLogLevel(null, preferences.getLogLevel(true), commitToFile);
    }

}

8. Remove termux-emulator JNI libs.
9. Need to move to semantic versioning. Check termux/termux-widget@af8b7c139. I forgot to add sha256sum when uploading APKs, so workflow needs to be updated, will try doing it soon.
10. Update .gitignore.
11. Add LICENSE.md. We should also explicitly include all used license files under licenses directory for all plugins. Also important if all maintainers get "hit by a bus" and nobody left to update urls. ;) https://www.gnu.org/licenses/gpl-faq.en.html#WhyMustIInclude
12. Enable minifyEnabled
13. The termux-shared import comments must exist for easier local development, check app/build.gradle and build.gradle. https://github.com/termux/termux-app/wiki/Termux-Libraries#forking-and-local-development
14. Use -all version of gradle instead of -bin.
15. Note that termux-shared library has been hugely refactored now locally, and all termux specific stuff moved to com.termux.shared.termux, so import statements and some other stuff will break when version is bumped. Also applies to other plugins that have been moved to termux-shared. Although, now only termux-boot will remain, which will get deprecated if/when systemd is implemented, so no point in working too much on it.

This should hopefully be enough for now, I'll let you know if I think of other stuff. Good luck. Do let me know if any further help or clarification is required.

Merging this now to make testing of the other PRs easier, will come back and look at the rest of the points later