Does choosing a very specific niche really matters?

Hello guys,

I want to start a blog after I learned some useful SEO. But I always see this: "choose a specific niche."

Does this really matter like will it affect the way Google sees my blog (if it will lmao)? What if I chased low volume keywords that someone new can rank for?

I want to choose something like TECH so I can write on the multiple things I know about ( I never focused on a specific niche).

Thanks for any help.