Part 1.
Here is the thing, whatever I am going to say to you is based on pre-covid knowledge. Right now, the AF is so full, I think they arent going to complete the latest OTS board. So its become very competitive and having a high GPA and a STEM major can only help. Having said that GPA only counts for 10% of your total score when they decide who gets a pilot spot. If you kick butt in the other 90% of your score, your GPA isn't going count as much. My son got a pilot spot in 2018 with a 3.0 GPA (non STEM). As of 12/31/2019, I would have told you that Is probably the minimum you need assuming you do well on your PCSM score. Today who knows. My guess is you can still get way with a 3.0, but the bigger issue with Covid and high retention rates, is that in order to even commission, you must go through Field Training. When my son went in 2016, everyone went. Today they are pickier so again the higher the GPA and the better the major (STEM) the more likely you will be invited. So while a 3.0 may get you a pilot spot, it may not get your past Field Training.
Part 2
People always ask what's the best detachment or which detachment will get them a pilot spot. The typical answer and the correct answer is always to choose the school first. If you don't like your school, you will be miserable regardless of the detachment. If you love your school, your detachment will be fine. Additionally, who is promising they will let your commission or you will want to commission by the end. So if you don't commission and now what. You are going to need a school that provides you with the best opportunities to get a job when you graduate. That may not be that detachment. Choosing a school by detachment can only work if all the other facts work out. There are too many ways that won't work out. Berkley while politically crazy, is a top-tier school and you were lucky to get in. Do your best the rest will work out