CreamyDog69

This, OP. Go where the science takes you and where you can stand living.

@Dank A great way to get an idea of where you'd be competitive is to ask a professor/senior researcher you've worked with where they think you should apply. You can get a decent idea of schools where you're competitive for that way.

Great advice, though, I doubt the PI is only like that with new students. New PI's generally keep their students close because their futures are significantly more intertwined with each other in a way someone with tenure doesn't have to worry about.

You do you. Don't know what you're asking for advice if you're not going to listen.

You've made it obvious that you don't have any concrete career plans. When you say " I'm passionate about science and technology, and I don't think I can get a satisfying career with just a bachelors degree ", it seems like you don't actually know what you want to do. Getting a PhD is a long haul and if you don't have specific career plans with which you know the PhD will help you achieve, you're setting yourself up for disappointment when you graduate if you don't have something very specific to work towards. Of course, your plans can change as you go through school, but you should at least have a more solid idea of what you want to do than being passionate about science and technology because that's a very big world with a lot of things in it. If you don't have those plans, you might as well be doing it for fun.

Cancer Bio

I guess find any weaknesses in your application and improve them? Ask a professor who is familiar with you that you think will be honest with you.

A few questions. Why not go straight for your PhD? If you have tons of research experience and decent grades, don't waste time and money on a master's. If you don't know what your career goals are or if a PhD isn't going to help you with those career goals, then I'm not sure getting a PhD for "fun" is a great idea. If your PI doesn't want you to have hobbies, I wouldn't say that's a good sign, plus, it seems like he's very intentionally dissuading you from joining his group. To do undergraduate work, a masters, and then a PhD in the same lab could signal to people in the future that you're unwilling to get out of your comfort zone. If you can, go to another school for your PhD and at the very least, go to another lab so you can see what else is out there.