Hi @WilliamA You could try wiping the cache partition , this deletes temporary files but not your data and may help. Follow these steps:
1. Turn off the device.
2. Press and hold the Volume Up key and then press and hold the Power key, in A series should not need to connect to computer.
3. When the Android logo displays, release all three keys.
4. An 'Installing system update' message will show for 30 - 60 seconds before the Android system recovery menu options appear.
5. Press the Volume down key several times to highlight wipe cache partition.
6. Press Power key to select.
7. Press the Volume down key to highlight yes, them and press the Power key to select.
8. When the wipe cache partition is complete, Reboot system now is highlighted.
9. Press the Power key to restart the device.
you can also repair apps from the sane Recovery Menu.
However did you do much research before purchasing the A12? The MediaTek processor is known to be a relatively poor performer but will predominantly be the case for Budget handsets. There are higher end devices n the A range , whilst the S series is the premium one.
A variety of Samsung devices reviewed in this article https://www.expertreviews.co.uk/mobile-phones/1407169/best-samsung-phone
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
