Article II, Section 4 of the Constitution says, "The President, Vice President and all civil officers of the United States, shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors." It does not say that the president or any of those other people cannot be investigated, indicted or tried for crimes. The Attorney General, during the Watergate Crisis, decided that the Justice Department would not indict a sitting president. All other Attorneys General have followed that policy. And, no one has ever said the president could not be held to answer to a state for breaking their laws. That is, until Barr said it. And, the Supreme Court, including both of President Pandemic's appointees said he is wrong.
I did read the relevant portion of the Constitution. And, now you have read it also.