I don’t believe there’s any way that reducing you clearance even with rollers that is less stressful on anything other than you mind…
The drag bars have a primary purpose, and that is to alert you of impending danger, stop you so you can readjust your approach or change the route all together…
They alert by making the loud objectionable noise of metal dragging…
If you fail to adjust they are designed to be the sacrificial lamb and will bend before damaging the frame…
The rollers in the picture above ensure the drag bars will be sacrificed sooner though may not hurt anything either…
Any rollers wheels designed to hold the rear of the trailer off the road can only increase the risk of dragging sooner and the following damage occurring sooner…
If the trailer is to low check for weak or worn suspension, frames that have lost their camber, under inflated tires, or poor design from the mfg.…
If it’s just too low for no good reason there are acceptable ways to raise them…