What replaced your Antelope Zodiac DAC?

Depends on the streamer / network player. Some are optimized for USB others for AES, I2S, LAN, etc.

For example, with my Schiit Yggdrasil, many owners prefer AES over it’s USB input, however I utilized it’s USB input because I was already invested in USB. In the case of my Denafrips Terminator, though USB is very well implemented, Denafrips suggests I2S as the optimal input.

Any of these outputs / inputs may serve you well, however if you want to push your system, matching the preferred output from your streamer / player to the preferred input of your DAC will likely be the best pairing (per the designers).

Just something to keep in mind. No need to make it a bottleneck in terms of making a choice (in case it presents in that way).

Since you are considering R2R DACs, you have many very good options. And in most cases, most DACs will allow for very good sound quality across their input set.

@1graber2 has given you some great recommendations. I recommend the top two levels of Schiit, all four Denafrips DACs, and the full Metrum DAC range. There are many others. All the best in your search.

great answers I didn't expect anything like those. My primary source will be a streamer, roon and tidal. if not usb then what? aes/spdif?

The better question to ask yourself is:

What source will I primarily utilize? Am I happy with it? If yes, then which output from that source is considered best?

Pick a DAC that complements not only that output from the source but also your overall system goals.

If you are agnostic on source, or will be moving in another direction (for example cdp to streaming) then what you choose should be based on the goals that define those aspects of the front end of your system.

But USB is not the best or even good for audio IMO.

This is NOT true.

Other than that, good advice and recommendations.

oh, but I would Avoid using USB into the new DAC unless you have a DDC (Digital to Digital converter), eg. running the digital audio signal from computer via USB to a DDC converter that allows you to then use SPDIF, XLR, or BNC from the DDC into your DAC. 

USB was initially pushed to be the main digital cable for Audio by the AV industry ONLY due to it's convenience and ability to be used in a broad range of capacities in tech. 

But USB is not the best or even good for audio IMO. The main reason that USB is deficient is bc of the 'Noise" it generates with the audio signal b/c the cord encapsulates both wiring for an audio signal and for power. 

In other words, buying a new R2R DAC and using USB will not get you the best sound you are looking for. In fact, it doesnt make sense to use an underperforming digital cable with a high-end DAC. 

i-Fi and Schiit make very good, very affordable USB DDC converters, and of course others are available. email me if any ??s.

I would start my journey by reviewing the MHDT DACs and the Border Patrol DAC, 
they have a great selection actually a little bit under your price range of R2R chip DACs, with options to add tubes to the stage, or balanced ins/outs, etc. 

http://www.mhdtlab.com

But these DACs are also sold via LTA: Linear Tube Audio, check their website too: 
https://www.lineartubeaudio.com/

and finally: the Border Patrol DAC
http://www.borderpatrol.net

best