Why is my ps4 crashing.

Try cleaning out your console. The first batches of the PS4 (first model too that came out around 2015) mostly suffer from the logic board overheating (Blue Light of Death) where the APU overheats.

To prevent this problem the console needs to be cleaned at least once every 1-2 years depending on how quickly dust accumulates in the console.

This is fairly easy to do by removing the black screws that hold the bottom cover in place. You’d probably want to get to the fan area so that you can clean the dust clogging up at both sides of the heatsink fans as that is where most the dust is:

更换Playstation 4的风扇

If you do plan to do this make sure you replace the old thermal paste and retain all thermal pads.

If that still doesn’t help it could be the power supply going bad over time from overheating which causes the sudden shut offs.

Thing is it could also be a bad hard drive from these symptoms. Have you tried re-initialising / updating the console and re-installing the games? Another hard drive can be used such as a 2.5” laptop hard drive.

This may get expensive to diagnose hardware wise so if software solutions are exhausted you may want to get a local reputable console repair shop to look at this for you and see if they can find the fault.