Maybe but it’s just a thought-terminating cliche that someone always throws out at any proposal at all besides shrugging your shoulders and accepting every problem.
I disagree, this is an objection that applies to this particular solution.
Its a global truth that corruption and tyranny is always a risk, but the amount of that risk varries with the solution proposed, and there are plenty of ways it could be mitigated to varrying degrees.
Devolving power to many smaller regional entities can offer a kind of open corruption that would be hard to pull off at a national level without attracting attention.