I recall seeing really long bolts to extend well down a suspension fork steerer
for agressive big drop downhillers to keep the front end bearing/and bars working and pointed the right way,
under those abusive situations.

maybe pushing down the quill adapter and tightening the band clamp is sufficient in your setup. ..

The Zoom/Satori threadless stem raiser uses a pair of half round wedges that friction grip the steerer ,

I tried it , at the time I thought.. the 2 wedge pieces which were round Beneficially could be made longer

extending far enough out to be gripped by a Bar Bag QR Mount.