I went through this process during a much different time so I imagine that there will be some major differences as far as the process goes.
I applied for dental school and the HPSP concurrently during 2008. At the time they had what was called the matrix qualification process. Essentially if you met a couple benchmarks, you we guaranteed the scholarship. GPA, DAT and an interview to make sure you weren't a *****. The very next year that all changed because demand for the scholarship went way up because the country had entered a recession. The matrix qualification went away. Obviously everything is different now. So I won't be able to be much help in that relm.
I did an AEGD-1, 3 years in Germany, and accepted a 2 year extension to take another overseas assignment (You have to commit to a 3 year assignment to go overseas so that added time beyond my initial commitment). So I did 7 years active duty and served in my top 2 desired locations. I would have separated at 5 years instead of 7 if they hadn't have offered me my preferred location. You can easily determine what your salary will be by googling military pay scales. You can also see what your BAH for any area will be based on available calculators. Add 20k for dentist pay. So base pay + BAH + 20000 + some other small things. The thing that will cause variance in your pay is your BAH, location. Your pay will be in the 120k range for the first 4 years. It goes up a bit after2,3 and 4 year and then quite a bit more if you are there past 6 when you promote to major. My last year I made 165K.
I pushed the button to separate in Feb 2020.... Terrible timing.... March to July of 2020 was a very stressful time for me. I ended up getting an associate gig locally with a practice who's dentist had to stop working the practice for various reasons during the pandemic. I essentially work as an "associate" in the practice from July until the purchase went through in Dec 2020. It ended up being great timing and am thrilled with my career path up to this point.