Phone is malfunctioning weirdly

Hey, I was playing a game yesterday and I mistakenly slept without quitting so my phone had shut down when I woke up. It's a Samsung s8.

I switched it on today and I found out my volume took more than 4 seconds to respond tho the buttons and my phone kept on saying System ui has stopped

sometimes after I pressed them.

I went to volume in settings and when I clicked it, the settings app went blank, phone got frozen for sometime and afters sometime responded but screen was still blank till I exited the settings app.

Sometimes I got lucky I could swipe down if the phone responded a little faster and I could adjust the volume buttons but the funny thing is it always went back to the level it was before I adjusted it.

The phone sound is not working too. I plugged in a headphone and even tried a bluetooth headset but still it gave me the same problem.

I went online and did all the requirements. Nothing worked so I had factory reset my phone and nothing was solved. I can't also install some apps because the download gets stuck halfway through. My phone is up to date too.

Please help me out.