If they truly want to do this, allocate by Congressional district or County.
This way, at least some semblance of conservatives in CA, or, to be fair, liberals in Texas, can have their votes count.
It might sound appealing that the winner of the national popular vote wins the election.
However, in a very close election, it’s not always clear who that is.
On election night 2000, Bush was ahead by about a million popular votes nationwide.
By the Wednesday afternoon, the day after election day, Gore was ahead nationwide by about 500,000 popular votes. That’s a razor thin margin, percentagewise, over the whole country.
In the 2000 election, a national recount would have been needed to verify who really won the national popular vote. Until that is done, you couldn’t even get to the electoral vote under these NPV proposals.
Ditto in 1960, Kennedy vs. Nixon. Officially Kennedy won the popular vote by about 100,000+ votes nationwide. But there too, if such a system were in place then, you would need a national recount. Who is going to supervise that, who would pay for that?