NOTE: I tried this, but links are broken and things don't work.. I tried googling those tough.
Phone: Umidigi Crystal (2GB RAM version)
I got an option under the developer options, to root. I checked it. Since I use Google Calendar, I would get double notification from the android calendar, I accidentally tought Calendar storage was part of Android's too. Turns out Google's needs it. Here are my attempts to restore it:
Trying to restore from unistaller: a)Corrupted b)There already is that package (have searched all / for those names, no result) c)Try again later
Factory Resetting the phone: It didn't come back.
Trying to install a downloaded version of it (via adb and from phone, locally): Something conflicting with signatures I guess:
C:\Users\Laptop>adb install C:\Users\Laptop\Downloads\com.android.providers.calendar.apk 5135 KB/s (441556 bytes in 0.083s) Failure [INSTALL_FAILED_SHARED_USER_INCOMPATIBLE: Package couldn't be installed in /data/app/com.android.providers.calendar-1: Package com.android.providers.calendar has no signatures that match those in shared user android.uid.calendar; ignoring!]
Trying to reflash: I have did, what I am told from multiple guides, but somehow SP Flash Tool just doesn't do anything.
Feel free to ping me for additional information, I really miss my calendar. I am all good with backups, so I can freely factory reset it. Right now I think, that easiest would be to get the flashing thing working.