I almost prefer backhand on a longer board.
The body dynamics seem easier to me.
In many ways, I consider surfing "backside" on a SUP, easier than "frontside"
To make any driving turn:
It is necessary to commit your body out over the rail.
backside you can hang your butt way past the rail and all the weight is applied directly to the rail, through your immovable heels (red line)
while your head and shoulders are leaning
back in towards the board. (blue line)

On a Frontside turn, your weight is also applied to the board through your heels.... but they are closer to the center of the board (red line)
while your head and shoulders must be way out past the rail to apply the same leverage (blue line)

I believe that "recovery" from a turn, is easier backside because your center mass is leaning closer to the board.
I think frontside is perceived to be easier because you are "looking" that way.
I am almost 100% certain that I cracked my neck a few years back on a bad head first slam into damp sand.... no insurance, so I just kept surfing

BUT... I have very poor head rotation, so I rely on good peripheral when surfing backside.
Please understand that I should be looking
much further left than I appear to be in these vids.
Here are two vids... one on a 9'4 and one on a 10'6
#1 is super slo-mo so you can see the way I move my feet to the heel-side rail when going backside (both vids do)
Also:
Heels do not bend under the pressure of a turn, so the force applied stays applied.
Heel-side rail control is rock solid.
#2 shows how much more I have to commit my body to a "frontside turn" when I cutback
The backside turns are a pretty simple "sit down" kind of move, that gets ALL my weight out over the rails and my heels transfer my weight to the rail.