Is it my streamer or does Audirvana sounds better?

I enjoyed Audirvana via a Mac Mini stripped down for music only, and was very happy with the sound. But I had technical issues with memory management and some other issues, so switched to an Innuos Zen Mk3 from TMR and didn’t look back. The Zen is a nice piece of gear.

How have you got your Garlubidor divinity r2r DAC and Audirvana set up?

Were you using USB from the T8?

Reading about the Audirvana it appears they have implemented excellent upsampling and noise reduction algorithms.  Is your DAC running "native" or upsampling? If the Audirvana was upsampling and the streamers were not, and your DAC is not upsampling the that could account for your computer sounding better.

Also, the T8 has a slightly hidden, but critical to turn on, setting that prevents the T8's Android OS from resampling everything to 48khz.   You must also configure the T8 outputs to support hi-res transfer to the DAC.

I'd suggest looking critically at your T8 and DAC settings to ensure you are getting the best SQ.  I use a T8 as the transport into an Esoteric K-01XDSE DAC and it is superb.  And DO USE USB.

When I first started to put together an ever-evolving system I used JBL305s and a JBL 310s subwoofie. I had some major bass phase or time delay issues that only Audirvana solved. I used the download non-subscription version. I really liked the usability as well- having my local files available and streaming presets. I have moved up a bit into bottom mid-tier equipment and moved away from a computer streaming-render source but let me tell ya lads, Audirvana on my MacBook Pro was good.

Audirvana 3.0 is excellent. I've been able to compare it using a M1 MacBook Air to my souped up Wim Pro setup. Prefer the wired method where I can upsample to DSD 128 or 256 frankly but my system is very sensitive and can take advantage of this. 

I'm not surprised that this type of Mac setup with Audirvana is challenging stand alone streamers in systems. Audirvana has a very good isolation approach through the computer and it simply sounds great connected via USB to my RME ADI-2.

This DAC allows for an upsampled DSD stream which frankly delivers better sound in my system setup. YMMV. 

You are trying cheap entry-level streamers, whereas Audio Nirvana is a software-based solution. Two things are happening. One is that you haven't really heard a proper streamer. For example, in roughly that price range but significantly better would be the relatively unsung but German-made Lindemann LimeTree Bridge 2. But made significantly better with an MCRU linear power supply. Secondly, what you are hearing likely is Audio Nirvana's software-based capabilities. And they of course sound very good compared to the cheaper hardware that you're comparing it to.