Essentially, in order for your Explorer to detect MQA and display the blue light, your Player software has to be "bitperfect"

Allowing the Volume to be controlled in that manner using Foobar means that the output is no longer bitperfect, hence the blue light does not come, when the volume is less than 100%.

The simplest solution to your problem is to use more functional Player software.

Audirvana and BitPerferct are examples of this for Mac... and likely have Windows equivalents.

An even better solution IMHO would be to try Roon, at least on their 30-day trial basis.

You can then use the Volume control within Roon to achieve MQA playback.

In addition, Roon's integration and use of Tidal needs to be experienced to see how much it offers... and most are very hopeful that Tidal will soon offer many more MQA selections from the more "popular" labels etc.

-