MQA won't allow full sw decoding although I am sure it is possible. Whilst I am sure many things are technically possible it is not what MQA are providing.

For full MQA the endpoint needs to be MQA enabled and if using DSP's they need to be the SE versions, in your scenario where the DSP's do 'some further decoding' what would be the case if you only had analog speakers as is the case for most consumers.

Russ