These three M’s are taken from an interesting book titled Symbols, Signs, Letters by Martin Andersch. The book is subtitled: About handwriting, experimenting with alphabets and the interpretation of texts. I can find scant mention of Andersch on the web, so if any reader can enlighten me do make contact.
It’s instructive to look at the illustrations, all from the 16th century, as being based on geometric forms. There are specific differences in the positioning of the mid-point and of the serifs, most particularly in the left/right balance.
This page re-directed me to The Geometry of Type by Stephen Coles (Thames & Hudson, 2016), which is an excellent guide to the different genres of type. Coles has 15 kinds ranging from Humanist serif to Script. Browsing, I came across FF Yoga Sans, which is described as ‘…a Gill Sans for the 21st century’. In other words it dispenses with Gill’s idiosyncrasies.