How do I end on negative friends & make new ones?

I have 2 friends only. I'll link the recent possible example of how their behavior is, on regular.

A girl, who is super qualified physicist & sees the world as if she's the only one eligible around. She disrespects all the facts that she doesn't know.
Example: We went to buy a new iPhone for me, & the store guy was showing us the unboxed iPhone 7 that I got. That's when she tried pressing the home button, and she thought that the taptic feedback is a 'defected iphone'. She was like, don't buy from here, they are trying to sell you bent phones, you should never apple anyway. I was like bit*h, just because your physics department's desk's make that wiggly noise, doesn't mean you have to be stupid yet confident about technology.

A guy, I know him since school days. At first he was cool, but now he has gotten so freaking judgmental. Every single thing I like, he criticizes. He literally starts listing down disadvantages of anything I come up with. Even if its a simple little thing, like a cool meme I send him.
Example: Hardwell, the famous DJ came to India today & held a concert. Now I'm really pumped up about this so I watch the entire live stream. I send him the link, he replied "meh. He just comes to india just so as he get votes from Indian population"
I mean, wtf. Dude came from Netherlands to show Indians some good time, and also donated the ticket money for children's education. Besides, I love his music. So for the sake of this, can't he just reply "ok. Cool"

What iPhone should I get?

I don't want the iPhone x because it's small in my opinion, so I was going to get the iPhone 8 plus. But should I wait for the iPhone x plus next year?

How do I change a phone bought from an individual seller over to my data plan?

I'm looking to buy an iphone 6 or 7 on Facebook Marketplace (I currently have an android and hate it) and was just wondering if I could just go to the verizon store after purchasing it from someone and ask them to switch the information for me? Would they do that? I'm looking to buy an iphone compatible with Verizon because that's the carrier I use

Added (1). Should I just buy an unlocked phone? I'm also looking on Amazon

Bluetooth headset not working with external microphone?

So, I have an aux cord plugged into my Iphone, which is then plugged into my 3.5mm keyboard. Which works fine on it's own, and with my speakers. But whenever I try to use my bluetooth headset it disconnects until I unplug my microphone. Any help?

Phone problems. View details

My phone decides to turn off every two minutes or so and shows the little spiny thing that it shows when shutting down. It then opens again and prompts me to unlock it. It does it again after another two minutes. It's an iPhone SE. Any idea what this is and how to fix it?