I don’t think the scrolling will ever work with mm1. The fact that it was possible somewhere along the iOS v.13 or so was rather a mistake that was quickly put in order :) Look, this thread has more then 35k views and apple still doesn’t give a jack about the issue. They simply want you to dig out of your pocket another 100 bucks for mm2. If you consider every one of the 35k viewers here buys a mouse worth 100 bucks, the sum is quite substantial ain’t it? There you have your reason as to why apple won’t fix the issue. End of the story.
Ps. At the time I wrote this comment iOS had the version mark of 14.2 and the scrolling on mm1 still hasn’t been solved.