Why gmail app crashing in my M30s. After cleaning data and catch still not working.

Why my galaxy M30s hanged for few seconds when i pick call on second sim slot. Sometimes for few seconds or until call disconnect.

After updating my M30s battery draining faster than usual. Is this probably created because of updation.

Why my M30s taking 6 hour to charge and 4 and half over when switch off. Is this software issue or battery. As i am searching there are other people's facing same problem. Please reply if it can be solved.