Your point: "Additive number patterns and sequences were the universal tool of Egyptian and Mesopotamian mathematics, and now prove their worth also when it comes to Mesoamerican astronomy and mathematics. They allow to work with integers, and provide many values from which you can choose the one that comes handy in a given calculation or number system. They are a very simple but clever tool. I saw no problem that could not be solved with those methods."
is refuted by the work of Ahmes. Read RMP 31,32, 33, 34, 35 AND 36 ...
Egyptian algebra was recorded in non-additive arithmetic methods ...
for example, RMP 31 solved an algebra problem that required the conversion of
28/97 that solved 2/97 + 28/97
with 2/97 solved by the 2/n table method that scaled 2/97 by 56/56 that considered 112/5432
and red auxiliary numbers (97 + 8 + 7)/5432 such that
1/56 + 1/679 +1/776
and 26/97 scaled by 4/4 = 104/388
and red auxiliary numbers (97 + 4 + 2 + 1)/388 =
1/4 + 1/97 + 1/194 + 1/388
and so forth,
Throwing out red auxiliary and other scribal methods with your modernized and over simplified views needs to be re-considered.
Ahmes' proof encoded RMP 35 that offered clear conversions of 2/53,3/53, 5/53, 15/53 and 28/53 such that the unity 53/53was first solved by finding 2/53 following the 2/n table method ... that selected 30/30 and soled 60/1590