I think both the streamer and DAC are equally important.
Most folks have access to ok sounding streamers (MACs, PC, iPads) and the intellectual attraction to “it is just bits, it can’t make a difference” is so overwhelming that most folks basically have to hear the difference a high quality stream can make to believe it. This usually happens after they own a high quality DAC. I did. I was instantly converted and never considered going back.
So, to soften the financial blow and focus on a single research project, it may make sense to get a really high quality DAC first… as it will produce a big upgrade… but then the streamer will also.