Are there scientific experiments, measurements on these? Which fonts make you read certain words twice, sometimes letter by letter? Fonts might also differ in how tiring they are for the eyes and brain. As billions of people spend hours reading day by day, even tiny efficiency improvements have a significant value, much bigger value than the one-off cost of designing a most efficient font.
Which font has clearly distinct lI|1, O0, rnm? To make reading faster, less ambiguous, less error/prone: can you design a font with visually more distinct signs: e.g. capital i, lowercase l, 1 (one), | (the "or" sign) should be more distinct; capital o [a circle] and zero [not only narrow, but also tapering, almost like a rhombus]; r before n: rn should differ from m, c before l: cl should differ more from d [the vertical line of d could continue further down; this way would differ from the mirror of b too]. q should have the right curve appendix from its bottom point to make it different from 9 and the mirror image of p.