It depends on if when you visualize e.g. an "8", you visualize something like a lemniscate turned 90 degrees, or e.g. visualize a number line, e.g. maybe a straight line with dashes at the 7, 8, 9, and with these dashes having e.g. some visual label, and so on.

I.e. if your "visualization" of eight is something like a picture, such that I can show you various pictures and you can say "yes, my visualization is sort of like drawing A, but also has such and such elements from drawing B", and so on, then, yes, this is clearly not total aphantasia. But if no such picture could ever have any similarity to your visualization, and you are somehow just experiencing some kind of non-pictorial "logic content" here, then, yeah, that sounds pretty aphantasic to me.