Overall everything comes down to how good you are either after bootcamp or any other form of learning. The times when you got job as programmer because you finished IT college are gone.
Good way to land a job is to contribute to the popular github projects as a start into the field. Because this is something that you can brag about.
Completing a bootcamp won't guarantee you a job. You're going to get out of it what you put in. Bootcamps have been trendy the last few years and companies are either shying away from them or having a steady hiring pipeline form them. Basically on your own you need to show technical skill otherwise having certificate you get from completing the bootcamp i just a piece of paper and reminder of wasted money.
It depends, some companies don't care what certification you have as long as you can show what you have done, for example side projects, etc.. others are more strict on the certification