Adding external DAC to AVR

Im going to try keeping it short My main focus when i build my system was movies.
I am running a Marantz SR8012 AVR, bi-amped to a Rotel RMB1585. With full lineup of the biggest Arendel speakers. Sounds great.

I used to just use the build in HEOS in the avr, but discovered Roon. And what a magical thing for music!

Now i have to use Airplay. This has its limist as everyone knows.

I have settled on going the RasberryPi route to build a Roon Endpoint. Looking at either Toppiing USBridge og Digione signature.

The Digione signature is straight forward. Just plug it into my AVR using S/PDIF and use the AVR’s DAC “AKM AK4458”.

But but but. I would love to be able to upsample to DSD and get MQA “Tidal user”.
AVR’s are apperently notorius for sending almost everything through its own dac, even when using analog inputs. It is my understanding that i can use “Pure Direct” on my avr to bypass this, but this shuts my sub off, this isent optimal in my setup.

I have been looking at a SMSL m500 dac that does MQA and DSD. But would i benefit by throwing this into my chain in some way. I am very confused

I hope there are some clever minds that can clarify this for me.