If you say there is nothing on the Presidential Election in the Constitution, you would be wrong, because there is plenty of relevant material in Article II.
Now if you said that States are allowed to set certain parameters of the election that are not delineated directly in the Constitution, you would be correct. But you did not say that.
Your point (much discussed on this forum) is that the Federal governnment has little to no control over certain aspects of the election process, such as Ballot Harvesting, Ranked Choice voting, how votes are collected, tallied, and resulted, and that is fair enough.
But saying we should leave it wholly up to the states is a mistake as well, especially since the Left controls the state election ballot process, and we have 22 states that have a Soros-backed Secretary of State in place (Last I heard)
My point was, there is only one Presidential election in the Constitution, it takes place in December since 1936, and since 1964 there are 538 voters. 535 of those 538 voters are appointed by State Legislatures, the other 3 are appointed by Congress.
In December 2020, 306 of those voters voted for Biden and he was thereby elected President.
Neither Article II or Amendment XII says anything about members of the public voting in a "Presidential election" in November, and that method could be dispensed with by any State or by all of them without infringing the Constitution by an inch.