Damage, if any, that may occur if the electricity gets cut off when playing the ps4

Like the title says, I want to know the issues that might occur if power gets cut off to the ps4 when using it.

There is always something downloading in the background when playing any games(usually update). I don't play multiplayer at all(internet is slow and unstable, high ping). Recently, the power got cut off and the external HDD was in use, playing NieR, and after the power came back, I turned on my ps4, it did the fixing thing, and showed warning and then when it was repairing the external HDD, it showed an error that it could not be repaired and because of it, the hard drive needed to be reformatted.( One thing to note is that the HDD was dropped to the floor before, but but enough to damage it.)

This killed me as I had to download 80gb of update again, and that would take around 190-200 hours(as I said my internet is extremely slow).

Now, getting an ups is great idea but currently I don't have the money for it. So I wanted to know what damages occur when power gets cut off when using it. Is there any safety thing Sony did? I have heard it does almost no damage but I want a proper answer.