I watched a bunch of youtube videos on it, but it's basic stuff

The colander change, unknown apps installed or the 3 dots on the corner of the screen, being there

But I seen online somewhere like my phone acts strange. Grant it, it's a iPhone X and they slow down the processes for sure, but my girlfriend brought it up my phone might be hacked (hilarious) so that's why I did some research.

Number one, sometimes, I won't get any calls from people who call me, like it won't even go through, there in my contacts
Next, when I call someone, it won't even ring, could be a wifi issue

If i'm on the phone for too long, like fall asleep on the phone, this hideous noise comes from my end of the phone, sounds like aliens

Is there anyway I can dig deeper into this? I'm just curious to see.