WASAPI exclusive mode - why different DACs do different things then

[pickyAudiophile]

Guys, I have a question regarding WASAPI exclusive mode playback by streaming services like e/g Qobuz and Tidal using their respective Windows desktop apps.
I experienced three different types of "behavior" when running contemporary DACs (ESS 90xx, AKM 449x, ROHM BD3..., no R-2R tried yet) with these apps' output set to exclusive mode:

1. irresponsive to Windows volume control (100% output, whatever the Windows volume slider is set to, responsive only to "mute" button), DAC device remains under exclusive control as long as app opened, no matter if music is played or not
2. responsive to Windows volume control, rest like 1st variant
3. like 2nd variant, but exclusive control only effective when music is played. If no playback immediately open to other sound output (Direct Sound, Windows mixer). - Even muting and resuming other sources in these cases works properly, as well as sample rate switch back and forth.

Q: Why is it like that? Why is it always unpredictable when buying a budget or quality DAC... Just neglectance by designers from DAC devices? Only the 3rd variant to me seems correct and as intended. Maybe not. Some might argue a mixture of variant 3 and 1 (there should be no truncative Windows volume control, still immediate unlock when no music is played to be expected).
Drivers at least do not make a change I found out. What do you think?

 

[MaxwellsEq]

Are you using UAC2 in all cases?

 

[pickyAudiophile]

Are you using UAC2 in all cases?

Yes. As far as I can assess, will at least all run properly above 96 kHz and can properly be preset to e/g 32 Bit 384 kHz by default or at least 24 Bit 192 kHz (depending on DAC device capabilities) at Windows device manager. Just one example for a "dumb" 1st variant DAC in front of me right at the moment: SMSL D300. One more "dumb" type: Gustard DAC A-18 right next to it. More type 1: Sabaj A20d 2022 not connected right now. Type 2 e/g dongle xDuoo Link 2 Bal, type 3 Douk Audio DAC-T1 PRO or even Sound Blaster X AE-5 (PCIe card). Plenty of other DACs tried. Unpredictable - but always within these three variants.

 

[MaxwellsEq]

It may not come down to budget or quality. It might simply be that the correct behaviour is poorly documented or open to interpretation. Similar things happen a lot when wiring together studio kit or network hardware from different vendors.