1month ago I received auto notification in mobile about battery replacement, after 1week mobile hanging using of any apps or normal settings now frequency of issue increased 5mins once,
Error like System UI not responding, wait or close app like messages, some time mobile automatically going off and switch ON.
I free the storage also ,now 32gb free in filemanager
This issue related battery failure or other components or software issue.
You were notified your battery was failing and you ignored it. It would not be unusual for a battery to fail after 4.5 years. Back up all your stuff before your battery fails completely. I'd say it's better to go for a new phone than replace the battery, as you would be at the end of your update cycle.
The phone told you the issue was your battery. Why would you think it's a software or other component issue?
As @nullandvoid has warned you, it's best to back up your device anyway you can. If you have a complete system failure you might lose the almost 5 years of stff on your phone.
