Wirelessly Connecting an iMac with TIDAL and Audirvana (flac files) to a DAC

I’m trying to figure out the best (and most cost-effective) way to wirelessly connect my Mac to a Cambridge Audio CXA81 which has an onboard DAC.
As my source, I use an iMAC with Audirvana playing flac files as well as Tidal.

Previously I had relied on a wired connection going from my Mac to an older DAC via USB then a long inter-connect going from the DAC to my amp. I’ve now replaced my old amp with a new one (CXA81) that has an onboard DAC and it’ll be located too far across the room for a wired USB connection. I’d rather not use bluetooth since, as far as I understand, even AptX is lossy.

One option is to get a Bluesound Node 2i. However, I’ve read that it does not support UPnP. But it does support Airplay 2. Is there a disadvantage (loss in SQ) to using airplay vs UPnP when listening with Audirvana?
I know I could also get the Cambridge Audio CXN2, but I’d rather not spend another $1K.
Is there a cheaper option than the Bluesound that would still result in good sound quality and allow me to wirelessly connect my Mac to the DAC in my amp?
Thanks for your help (and patience) as I try to figure out how network playing works.

Thanks, Erik.  However, I'd like to avoid paying for the Roon subscription. And it still doesn't solve the need to first figure out the hardware solution. 
I know, the subscription fee was a stumbling block for me, but it seamlessly integrates Tidal with all my ripped tracks, plus adds DSP EQ capabilities so in the end I caved.

I use a Pi 4 with Ubuntu Linux ($150 including memory card) to stream via wifi to my USB connected DAC. You could use your Mac as the servers or buy a slightly beefier box than the Pi for this.
Post removed 
This probably isn't a solution unless you could find a used one, since it was recently discontinued, but I stream from an iMac in my office to an Arcam rPlay in my living room and connect the coax out to my Bel Canto DAC 3. Works flawlessly and sounds great.
You could use the Node2i wireless or wired. You don't need Audirvana to use the Node2i to stream your Flac files or tidal.
Thanks, @djones51. That makes sense now. Didn't realize that streamers can just find the files on your mac and wouldn't need a player like audirvana. Seems like the Node2i is a good way to go.
Just need to make sure your music folder is shared using the SMB protocol.