(Even though the process below of setting the box up may not be simple/basic, hopefully the resulting setup will be. You do not have to install apks or disable apps like I did, but hopefully the options are laid out to be helpful.)

I just wanted the box to run a browser and two side loaded apps (let's say A.apk and B.apk, for example A may be SmartTubeNext). To keep everything simple and minimize resource usage, I disabled what I don't really use: Google Assistant and search (Google app), using a phone as a remote (Android TV Remote Service), and even Chromecast (Chromecast built-in).

I also did not want to install and deal with ADB or a third party launcher. To remove ads, I disabled Android TV Core Services (sponsored/promotional channels) and blocked androidtvwatsonfe-pa.googleapis.com (so a DNS lookup from my router returns 0.0.0.0; many people do this through Pi-hole).

Some may also suggest turning all three animation scales off. But I am not sure it makes much difference versus the effort/risk going into Developer options.

• https://www.reddit.com/r/AndroidTV/comments/6i6ag7/making_your_android_tv_smoother_snappier/

Brand new / initial setup:

• Download 680 MB (Security Patch Level Update Feb 2022).
• Later, on Home screen, right of Updating apps: Update your remote > Details > Continue
  • Settings > Remotes & Accessories > Onn-Remote (shows Version V1.44)

If factory reset later:

• Settings >
  • Accounts & Sign In > Google > Remove account > OK
  • Device Preferences > About > Factory reset > Factory reset > Erase everything

Rest of setup:

• Sign In
• uncheck Use location, Help improve > Accept
• Google Assistant:
  • Search across: No thanks
  • Get personal results: No thanks
  • Get the most: No
• uncheck Install all (but cannot uncheck Hulu, HBO Max, Prime Video) > Continue
  • Can leave Send files to TV, TV Bro, and X-plore File Manager checked (they may show up if they have been installed previously), then will not need to install them individually from Google Play website later.
• Right button four times > Control volume and power with your remote: Not now

Install apps:

• From Google Play website, install to the box:
  • https://play.google.com/store/apps/details?id=com.yablio.sendfilestotv
  • https://play.google.com/store/apps/details?id=com.lonelycatgames.Xplore
  • https://play.google.com/store/apps/details?id=com.phlox.tvwebbrowser
• Apps >
  • Send files to TV
    • /sdcard/Download = Internal shared storage/Download of X-plore File Manager
    • Back button > Receive
    • From a phone (with Send files to TV installed and apks downloaded), Send: A.apk, B.apk.
  • X-plore File Manager
    • Install: A.apk, B.apk.
    • Use "Mark files" to select file(s) to delete instead of entire folder.
    • Requires donation to access Server for WiFi file sharing and FTP. So use Send files to TV.

Settings >

• (Suggestions: Set your device name > Enter custom name > - only used by Chromecast?)
• Accounts & Sign In > Google > Choose synced apps: Off/Disabled for all
• Device Preferences >
  • Google Assistant > Off
  • Security & restrictions > Unknown sources > A->On, B->On (if they can update themselves, such as SmartTubeNext)
• Apps >
  • See all apps > Disable, Clear data:
    • Android TV Remote Service (if updated, shows up under system apps, Uninstall updates)
    • Camera
    • Disney+
    • Gallery
    • Google Play Games
    • Google Play Movies & TV
    • HBO Max (Uninstall)
    • Hulu (Uninstall)
    • Netflix
    • Prime Video (Uninstall)
    • Send files to TV (Uninstall, because it runs all the time)
    • YouTube
    • YouTube Music
    • (afterward 6 apps remain: A, B, Google Play Store, Movie Player, TV Bro, X-plore)
  • Show system apps > (if updated, Uninstall updates), Disable, Clear data:
    • Android Accessibility Suite
    • Android TV Core Services
    • Chromecast built-in
    • Google

Home screen:

• Add to Favorite Apps by selecting + at end of Favorite Apps.
• Can long press on an app to Move it.
• Customize your Home screen: Choose channels >
  • Play Next->Off
  • (SmartTube > Recommended->Off - if SmartTubeNext is installed)
  • (Promotional channels > App Spotlight->Off - not needed after disabling Android TV Core Services)

That's all. By the way, I picked TV Bro after also trying "TVWeb Browser for TV" and "Downloader". I could not test Silk Browser from an apk on my phone, and Firefox TV from an apk had a big banner about ended support.

As to removing ads, if "Android TV Home" had been running before you blocked androidtvwatsonfe-pa.googleapis.com, you want to Clear data of "Android TV Home" (and you will need to set up Favorite Apps again).

• https://www.reddit.com/r/ShieldAndroidTV/comments/o64627/i_managed_to_block_the_ads_on_the_new_home_screen/
• https://www.reddit.com/r/AndroidTV/comments/mvqbnk/how_do_i_turn_off_this_new_android_tv_update_i/gw2g7wv/

I actually don't know what "Android TV Core Services" really all do. A few references I found:

• https://android-tv-core-services.en.softonic.com/android
  • "updating the core services used by Android TV devices, such as the YouTube, Google Play Music and Google Play Games"?
• https://www.reddit.com/r/bravia/comments/b6ponh/sponsored_row_just_appeared_on_my_home_screen/
• https://www.reddit.com/r/AndroidTV/comments/mvqbnk/how_do_i_turn_off_this_new_android_tv_update_i/

Finally, if your Select button on the remote is low: The edges of black (D-pad or Up/Down/Left/Right) and white (Select or Enter) buttons should be at the same level. But the Select button on one of my remotes was low. It bothered me enough that I popped the remote open (open the battery door to see where to insert a pry tool), and added the height of two regular 20 lb pieces of paper under the Select button.

• To reassemble the remote, start with face plate upside down.
• Place black piece (D-pad or Up/Down/Left/Right) onto face plate.
• Place white piece (Select or Enter) onto black piece.
• [Add four small triangle paper pieces, two layers, onto cavity of white piece.]
• Place rubber sheet/panel with buttons onto face plate and black and white pieces.

Misc notes:

• Spec: https://www.androidtv-guide.com/streaming-gaming/onn-wallmart-android-tv-uhd-streaming-device/
• Customizations: https://www.reddit.com/r/AndroidTV/comments/q9mfz8/list_of_customizations_for_walmart_onn_4k_box/
• Remote:
  • In the Quick Start Guide (green cover), the button with a gear is Settings, but is misprinted as Input.
  • To un-pair a remote so can re-pair with the same or another remote, can press a round button on the side of box for 3+ seconds.
  • The remote has a Mute button (a user may press it by accident).
  • To restart, can long press Power button > should see Restart on screen, Select button (faster than Settings > Device Preferences > Restart).
  • While on virtual keyboard, to enter an upper case letter, can long press Select button (instead of moving to and selecting the shift key first).
• For TV Bro, User-Agent strings can be seen in:
  • https://github.com/truefedex/tv-bro/blob/master/app/src/main/java/com/phlox/tvwebbrowser/activity/main/SettingsModel.kt
  • "Chrome (Mobile)" and "Chrome (Tablet)" may be swapped.
• SmartTubeNext supports, under Settings > General, "Boot to section" and "Set[ ]up sections".
  • One can save a live stream in Playlists > Watch later, so it's easier to access again.