Ask HN: Do I need to write a cover letter?

I have been working for 3 years now as a software developer and I have applied to countless jobs. I feel like the fact that I didn't really put too much effort into seeing if the job actually was a fit or not actually helped me not spend too much time on having to filter jobs. I just applied for everything and some companies replied while others didn't. I have a friend who is looking for a job in the pharma industry in Switzerland and I was thinking she could apply the same method. I feel like spending too much time in filtering what job might fit and what won't is a huge part of why people don't like looking for a job and they end up not looking for a job instead of just trying even if some of the random applications will be a total miss.

What are your opinions on the matter? Are there any articles about this kind of stuff?

I guess the more broader context is quality vs quantity? I tend to prefer quantity and prefer to filter at later stages for the quality...