It is not as simple as that. In most cases maximizing the radius out would also increase the
moment of inertia. Moment of Inertia is 'resistance to rotation' around a specific axis. That means that your arm and racket would resist rotation for a given force and slow down the acceleration.
The pros have worked through the trade offs and do's and don't's with what they are doing and we can see it in videos. I would say that they don't put their upper arm down close to their bodies for forehands or 1HBHs so that the radius out
is not minimized. Also, the ideal camera view would be from a camera above the player looking down. Many high camera views will give you the idea of the forearm to racket shaft angle at impact, especially for Semi-Western and Western Grips. For Semi-Western and Western Grips the racket shaft is at an angle to the forearm, that does not maximize radius out. The straight elbow forehand does more radius out for given upper arm down angle. The Semi Western Grip allows simplified adjustment of closed racket face for impact - try it and see how simple and direct adjusting the closed racket face tilt is. Look at videos of ATP players and see what you see. Pick a model forehand player and see what they do. Observe whatever the ATP players do.
The 1HBH also does not tilt the upper arm down too much. Thread -
One Hand Backhand - Waht Force to Start Forward Swing? See Mojo28 vs Gasquet 1HBH comparison post.
If you want to start viewing high speed videos of forehands read this recent post.
Your side-to-side (azimuthal) shot variation might be more controlled if you used Djokovic's rotations as he does.
Djokovic's forehand is a 2 phase stroke.
Rotations
1) Timing of the uppermost body turn (seen by the line between his 2 shoulders.)
2) Timing of his shoulder joint use. (seen by how the upper arm first starts at the shoulder joint.)
To single frame on Youtube, stop video, go full screen, use the
period &
comma keys. Does not work on phone Youtube.
Watch for #1 and #2 and how he times them.
First his uppermost body turn #1 begins and later his...
Safety - These strokes involve twisting and untwisting the spine and that may be too stressful for many players.