The State Legislatures do not have the power to overturn election results. The theory is complete legal bunk.
"It is this near‐plenary power that Eastman and other supporters of the former president have claimed gives state legislatures a blank check to overturn their state’s election results as well. In other words, Republican state legislators could convene and award electors to Trump’s slate even after the voters chose Biden. Some have pushed this theory so far
as to claim legislatures can somehow revoke their 2020 electoral votes right now, long after the election is over and Biden has taken office.
That is patently absurd, and to their credit it has been rejected by Republican legislative leaders in states such as Wisconsin.
Even in its more limited form covering the period between Election Day and Inauguration Day, Eastman’s theory ignores the plain text of the Constitution in an attempt to empower state legislators beyond their constitutional limits. State legislatures get to decide how electors are chosen, but Congress gets to say
when electors are chosen. “The Congress may determine the time of choosing the electors,” as Article I succinctly puts it. Congress
has done so by designating the first Tuesday after the first Monday in November, otherwise known as Election Day.
Election Day is the deadline for the states to pick and implement their chosen method for appointing presidential electors. After that, state legislatures have no further say in the matter.