Like mkb712 when I play my dreadnaught I look somewhat like

https://ibb.co/njWhW5

If I remove my fretting hand from the neck, it will fly away (slowly) from my body from the force of my picking arm resting against the guitar body. To keep it from doing this, I must slightly place my thumb or index finger on the fretboard. If I'm fretting a note, the force of the finger pushes the neck back in and against an opposing thumb. But then if I need to play an open higher string, I need to clasp the neck with my thumb. But when playing open and fretted higher strings, I don't have time to move my thumb back and forth, so it ends up staying over the top sometimes leading to fret buzz.

Any suggestions for my dilemma?