I bought a "samsung j5 prime" in October 2017 and its initial operating system was Android 6.0.1
At that time, the only problem with this mobile was the high battery consumption
A few months later, Samsung provided android 7 (nougat) for j5 prime - I updated my phone for a new update in the hope of fixing it high battery usage
but not only did not fix my phone's battery problem, "the hanging - lagging - some times reset" problem was added to it
A few months later, Samsung provided android 8 (oreo) for j5 prime - I updated my phone for a new update in the hope of fixing it "hanging - lagging - some times reset - high battery usage"
But only 50% of the battery problem was solved and hanging and some times reset problem was solved
now i have lagging and delay in performances problems
for example when i want to moving between active apps windows , active app windows will appear with a delay of 2 seconds
when I want to use the keyboard, keyboard letters will appear with a 3 second delay
And the handset is very slow and very lagging
I've already factory reset it twice but my problem was not resolved
now i want to downgrade my android oreo to android 6.0.1
but I'm scared
Because I read in some of the forums, After downgrade, there will be problems with mobile
for example "imei null - network problem - frp problem - ringing problem - ..."
what should I do?
Put the phone in Safe Mode which disables your downloaded apps and leaves the stock ones working and then see what happens in Safe Mode.
If the phone improves then one or of your apps are conflicting.
Come out of Safe Mode and start deleting your most recent apps one at a time.
But if the issues remain in Safe Mode then I'd suggest to use a Samsung Experience Store or Samsung Service Centre.
In regards to rolling back firmware Samsungs official stance is that you cannot.
I can't advise here how to roll back firmware.
Please use Google Search and or look on the xdadevelopers site to learn how.
A person doing this does so at their own sole responsibility knowing that a phone can be put Into an unusable state and possible manufacturing warranty being voided.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.