My phone got slower and laggy after I downloaded WhatsApp. Is there any way to fix it?
I recently bought an Xperia XZ2 Compact and last night I downloaded WhatsApp and with my backup, but just after downloading it my phone got slower, laggy and I feel like the screen is not as sensitive as before because sometimes I have to click a couple of times to the Home button and sometimes in the high brightness, some lines appear they are all the same but between each two there is a comparatively grey part but you can still see the screen, it just looks weird. I read online that maybe WhatsApp has been working in the background and that's the reason why, but when I turned off the Wifi and Data it didn't seem to change. To fix it I deleted some many applications including the ones came with the phone. Also, I restored to factory setting for 2 times to solve the issue. By the way, I haven't updated my phone since I bought the phone and my Android version is 8.0 Oreo. I wanted to ask if there is a way to fix it without deleting the WhatsApp since I use it a lot. I would really be happy if someone could help me.