...this is an easily overcome problem. Harris would simply move her voter registration to the District of Columbia.

having a both from the same state being a no go. It really does not matter if Harris is also from California, the state will vote for her no matter what.
Her having her registration in DC would mean nothing, California will go vote for her.

There is nothing illegal about both being from the same state, and in this case it does not even matter.

There is two reasons why in a normal election that its not done. One is spread out the popularity to a second state, aka if the Vice Pres candidate is coming from a state that has elected that person by wide margins. Its to get the voters on that persons party energized to vote and effect the vote if its a swing state or region.

The second reason is if both are in elected positions already they dont want two empty offices, especially if they are something like a member of congress.

Now there can also be said there is a minor third and fourth reason. 3rd is there could be people who dont like say California and feel the California ideals dont match theirs. Then we get in to the simple east vs west ideals.

Would Harris be smarter picking someone from the rust belt to appeal to it, maybe, same as picking someone from the east coast might be better.

https://www.history.com/news/can-the-president-and-vice-president-be-from-the-same-state

The 12th Amendment that changed the process for voting for a vice president left in place the rule that a state's electors can vote for only one of the two people on the ticket that are from that state. This means that California's electors could vote only for Harris or only for Porter. This would put the state's 55 EVs at risk even if they'd won the state's popular vote, and it's the real reason why candidates don't pick running mates from their own state.

This is humor, and imo, it's a very witty reference to Trump's fear of both sharks and things that are powered by electricity.

Otoh, if you're saying "no thanks" to Kamala, you are probably posting on the wrong site.