There was a company on Ali, that was selling a bearing nut for ER32 and smaller. Nothing to catch your hand on if you cover the area between the nut and the body where the extra thread is. In China and else where , they are making these bearing spanners that have either a lever or switch for the different directions, or else you need to turn the spanner over. They make the matching Nuts and spanners for the ER16 and the SK models, up to ER32 or the equivalent . An ER32 nut is 70mm diameter I think it showed, I have some and they work very well. Will get some more in the future. A lot of brands are making the one way bearing spanner now. BIG make them for some of their range, in particular the mini collet holder, for holding the drills on a 1.5mm shanked drill bit and the smaller 0.8mm shank series drills or cutters etc
A search for Bearing wrench , will show up the results.
Neil