Had the same issue with my TP and Iris after updating the firmware. Your choice is to undo the firmware update or ditch the Gaia or as was suggested to me by Denafrips - buy an newer version of the Iris. Obviously I made a mistake buying the first one why would I repeat it?
I did not like their response and sold the Denafrips gear. It was nice sounding but they lost my loyalty.
I have a Lampizator DAC and Antipodes S20 DDC. Unfortunately chip shortages forced Antipodes to stop selling the S20. It, like the Lampizator, is in another league than Denafrips.
In hindsight I see it as a blessing, and I am much better off now than if I had stayed with Denafrips.

