Hello,
As of R2024a, you can turn off the fading effect of inactive variant choices by setting the "VariantFading" value to "off".
set_param('bdroot','VariantFading','off')
'bdroot' is the current active model. You can specify any other model name as well.
Here's the documentation link for the same: https://www.mathworks.com/help/simulink/ug/set-and-open-active-variants.html#:~:text=set_param(%27bdroot%27%2C%27VariantFading%27%2C%27on%27)
