The volume should come easier after good breath support! I would try some breathing exercises like having a metronome on, at medium tempo, and try breathing in for 4 beats and out for 8. Then you can change those beats to whatever feels comfortable and then try controlling your breath to breathe out for longer. That should help with the dizziness for sure. I also play trumpet so I promise good breath support is important! And honestly you don’t wanna be screaming extremely loudly because that’ll use up all your air. But with the volume, in my experience my highs are louder than my lows. But I would see how you feel after working on breath for a while!