How bad is bleach for the hair really???

I have never dyed my hair before, don’t even use heat products and it’s super healthy! For summer this year I want to go light brown more blonde tones but I’m scared my dark brown hair won’t handle the bleach

I have a few worries 1) my hair will become super dry and fall out 2) I will never get my natural hair tones again as I have natural highlights 3) my hair will become brittle in the future 4)My hair is also already impossible to curls/style as it is dead straight hair will beaching it make it harder??

I just am a little scared as even since I was little my family has always said it will ruin your hair forever!! But I want to try something different!

If anyone has any info or past experiences that would be great also I don’t know if this was the right subreddit to post on xx