They Think Hazrat Ali (as) is god (nazubillah)
The Shia sect DOES NOT believe that Hazrat Ali is god. To believe that he is the Wali of Allah, they do have to believe in Allah right? This story is not baseless though because there is an entirely different sect of Muslims that are called ‘Nusehri’ or ‘Ghulat’. Their belief is that Imam Ali is god. Their beliefs are deemed deviant and wrong by Shiite scholars and they are not part of the same sect. Moreover, Hazrat Ali (as) famously said that there will be two type of people. The ones who exaggerate his attributes and the ones who decrease them. Both are wrong.
They Have a Different Kalimah
Most people do not know this but for a Muslim shahadah, the Kalimah you recite is the second kalimah you memorized as a child. The Kalima e Shahadah defines your faith as Muslims, and the Shia Muslims have the same faith. Thus, they also have the same kalimah.
There is a difference in the first Kalimah because Shia Muslims believe considering Ali (as) the Wali of Allah is their completion of faith. Qari Ishaq was the Grand Mufti of Pakistan and identified as a Sunni Muslim. He explains this better than anyone: