My question is : what do you say to be a number?
You cannot treat numbers before knowing what they are, and giving a meaning to such infinite way of writing.

My answer would be " a point in the real line, in which I fixed a point 0, and a point 1, in order to have the unit to measure segments with"
In this context, which number is 2,99......?
BY DEFINITION, it is the limit of the points given by the succession
2
2,9
2,99 ...
so that your arguments prove indeed that 2.99999...is 1.


Interesting to me, the discussion here is similar to that historically happened about infinity "in fieri" = latin,for "becoming" and "in acto" (not sure) = "already existing".