No, the president is not immune from indictment, as we've mentioned before that means he can choose to slaughter the entirety of the federal government and seize power at will and have that be 100% legal. The only thing that makes this argument are DOJ opinions from two presidents explicitly worried about being indicted.
There is absolutely nothing in the Constitution that precludes Mueller from stating he would have chosen to indict Trump absent DOJ guidelines.
Do you have these paranoid fantasies often?