To quote Dr. Hossenfelder directly: "In standard quantum mechanics the measurement outcomes will be non-correlated. In a superdeterministric hidden variables theory, they'll be correlated - provided you can make a case that the hidden variables don't change in between the measurements." [1]
That last sentence is the catch here: in case the experiment fails to show any correlation, it can always be argued that the hidden variables changed for whatever reason. If the calculated theoretical boundaries (e.g. temperature & measurement time) are insufficient, there's still no way of telling systematic errors from falsifying the initial hypothesis. It's little details like this that theorists can hide behind while still shouting "Foul!" from the peanut gallery.
Since experiments cost time, money, and pin down talent, research facilities need to be picky about what they test. "Because I like it." [2] is not the most compelling argument when trying to make your case ;)
I wonder whether crowd-funding would work in this case...
[1] https://backreaction.blogspot.com/2013/10/testing-conspiracy...
[2] https://www.fetzer-franklin-fund.org/wp-content/uploads/2014...
A lot of really really smart people tried to solve this by experimenting more. It didn't work. It's time for philosophy again, and in my view, also to accept that the weirdness is not going away. Nature doesn't care about what we find weird or not.
As for the author of the article I've never seen a clear proposal but it appears the idea is to do repeated measurements that display quantum effects while reducing noise as much as possible and check if there are deviations from quantum theory.
EDIT: found a more concrete proposal http://backreaction.blogspot.com/2013/10/testing-conspiracy-...
Besides to put a person in a superposition may require a machine as large as the universe, so you get issues with the speed of light.
The only way to test MWI is multiverse immortality - many worlds means you should expect to always have some future experience - there is no real death.
EPR experiment does exactly that. In fact, it's a good experiment to get intuitive understanding of MWI.
In standard QM says the measurements should be completely uncorrelated, but she argues that in a superdeterministic theory results somewhat correlated.