Is increasing the number of times one recites Ayatul-Kursi in the morning and evening remembrances an innovation (bid'ah), by reciting it three times instead of once?

The Sunnah is to recite the morning and evening remembrances (adhkar) that are restricted to specific numbers as they were transmitted, so nothing is added to them, nor is anything subtracted from them, nor are their wordings changed. Intentionally adding, changing, or subtracting and adhering to that is an innovation (bid'ah).