Keep in mind that the SMSL I initially recommended is a DAC and headphone amp (so essentially will duplicate the amp function of the A90).
It measures well though. If you only want a DAC with MQA and balanced out the SMSL SU-9 DAC MQA is indeed a fine contender.
The question is if you will notice any sound improvements from MQA at all vs a normal stream. Potentially a cheaper non-MQA dac with good measurements combined with the A90 will provide exactly the same audio quality*. Going with a cheaper DAC like the Topping D10s/E30 or if you want balanced D30pro or Schiit modius could save you some money. The Topping D10s and Schiit modius don't offer a volume control / remote. Depending on your use case a remote could come in handy.
* Not trying to start a MQA debate, just something you should determine if you find it necessary/useful ;-)