Others have pointed out that it is not dangerous, so I’ll point out that it is emensely rewarding to do this kind of work yourself. Enlist a competent buddy and give it a try.
Do modern cars have anything to mitigate this?
I've worked on the brakes on multiple cars and never once took one out for a test drive without triple-checking that I didn't make some stupid mistake that would put other people in danger.
Don't get me wrong, I had a couple cars with dodgy brakes over the years but always made sure they were good enough at the time I was driving them -- had this '53 Dodge that I had to bleed the brakes every time I wanted to take it out for a spin because the wheel cylinders were pitted and slowly leaked but always made sure to do a proper job because other people's lives were at risk too.