Apps automatically close

Thanks for your last screenshot: you are having an issue to log in to AppleID/iCloud.

1. Open Settings.
2. Tap your name
3. Scroll own and tap Sign out

Restart you phone, for good measure.

Then repeat the same steps to sign on.

you may have a hardware problem

First try a forced restart

https://support.apple.com/guide/iphone/force-restart-iphone-iph8903c3ee6/ios

If that does not help the  next procedure would be to backup then restore your device to factory, and setup the device without restoring a backup, to see if the issue is replicated. 

Then restore the backup.

Here is a guide for those steps

Backup and restore

(1)How to back up your iPhone, iPad, and iPod touch – Apple Support

(2) Restore your iPhone, iPad, or iPod to factory settings – Apple Support

(3) Restore your iPhone, iPad, or iPod touch from a backup

If that fails arrange a repair

https://support.apple.com/en-gb/iphone/repair/service

but in your case it would not be reparable.

I imagine that you have already tried to restart your iPhone, in which case I would suspect that you are running low on memory. To check whether this is the case:

1. Open Settings
2. Tap General
3. Tap iPhone Storage

The 1st section will show you how much memory your phone is using. The other sections, under apps, will show you how much storage each application is using.

It's up to you to decide what to do with apps that consume large amount of memory, i.e. keep them or purge some of their data.

You mean ios12.5.1 I think.

Settings, Battery, Battery health

What %?