Your grasp of the Constitution is shaky, to say the least. Article II, Section 1, Clause 2 provides as follows:
"Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors, equal to the whole Number of Senators and Representatives to which the State may be entitled in the Congress: but no Senator or Representative, or Person holding an Office of Trust or Profit under the United States, shall be appointed an Elector."
If a particular state's legislature were to establish that the "manner" by which that state's electors were to be appointed was by a plebiscite conducted among that state's eligible citizens, then that's how it would work, perfectly consistent with the Constitution, in that particular state.
Even in the very first presidential election, in 1788-89, a number of the states (not all, but some) "appointed" their electors by the manner of a popular vote.
What is your source? Asking (again)... to see if there are paragraphs.
OVER-
[ I am not a grammar cop, nor did I ever play one on tv, and I am NOT going to stay at a Motel Six, tonight, where they will leave the lights on for me, BUT, I respectfully ask for your source as I would like to read the material in its natural form.
Yes, allowing a popular vote is certainly an option for a State Legislature to carry out its job of appointing Electors.
The Legislatures of Arizona, Wisconsin, Michigan, Pennsylvania and Georgia did that in 2020, and not a single one of them disputed the result.