Why can't I uninstall/disable all bloatware through ADB without root?

I recently tried to disable bloatware in my cheap Vivo and Oppo smartphones. These apps named Themes, Game Center, Hot Games, etc. keep giving me notifications that can't be disabled through the UI. The notification settings are on by default and greyed out (can't be changed). And obviously the application can't be disabled/hidden with the menu either. *(To at least suppress the notifications, see **Edit** at the bottom.)* Using ADB, I tried the usually recommended commands such as pm disable-user --user 0 com.bbk.theme and got hit with: Exception occurred while executing 'disable-user': java.lang.SecurityException: Cannot disable com.bbk.theme no root permission I was confused, and googled the issue. Based on XDA and Reddit threads I read, the claim that ADB being able to disable/uninstall everything without root is basically a myth. Some people also experienced different errors such as Failure [DELETE_FAILED_OWNER_BLOCKED] or Failure [DELETE_FAILED_USER_RESTRICTED] For certain apps, manufacturers have disabled this method and several other workarounds. Like the workarounds mentioned in https://stackoverflow.com/questions/72006988/pm-uninstall-k-user-0-failure-delete-failed-user-restricted . None of them works anymore, even the freezing/ignore RUN_IN_BACKGROUND one. The often-suggested Canta and Shizuku on online threads also didn't work. So I wonder, why can't I uninstall/disable all bloatware through ADB without root, even though most people online keep insisting that this works? Some of my guesses for the reason: 1. The method still works with popular brands like Samsung. I haven't tried doing this with Samsung though. 2. Only the cheaper models have this issue. Because these bloatwares offset a lot of the manufacturing costs. 3. Regional difference. Perhaps some laws like EU's DMA prevent this issue. 4. The method still works on *some* bloatware. So people just assume it works for everything. 5. The internet commenters have older phones. Perhaps the manufacturers didn't disable this method back then. Perhaps someone more knowledgeable knows the actual answer. ----- ***Edit**: Digital Wellbeing's Focus Mode and Dashboard (0 allowed minute) can mostly suppress these bloatwares' notifications with some weird effects, because these bloatwares are considered as the "default applications" for things you do with the phone. For example, opening play store links by default opens these manufacturers' own app marketplace. Even though Google's Play Store is installed. Another example, trying to interact with files and images will trigger these manufacturers' built-in file managers and gallery, even though alternatives are installed. Of course these attempts failed, because the 0 minute restriction from Digital Wellbeing. Making you unable to do what you meant to do. Btw disabling their ability to open the relevant links under Default Applications doesn't work. Simply awful.* ***Edit 2**: That didn't last long. Now, Oppo's App Market kept giving me app recommendation notifications despite Digital Wellbeing. Same with Oppo's Weather Service. Both notifications can't be turned off. Really nasty stuff. Asking local forums just get me the usual "Just use ADB!" or virus accusations. At least Oppo's sketchy loan app Fineasy can be manually uninstalled on my phone. I heard some people weren't so lucky. I also read the news about Thailand Government banning that Oppo's shady app. Good for them.*