streaming and audiophile stereo

I would start small with a blue node like mentioned above, just don’t waste your money on expensive Ethernet cables and so called audiophile Ethernet products, they don’t work.

what you may want to consider since you are using tubes, is to move your wireless router away from your equipment. Some products are poorly designed and pick up noise from the radios in the wireless router. 

In a digital source chain the streamer is probabaly most important, try a reasonably affordable all-in-one streamer/DAC like a Lumin T3 that has very good digital outs via USB and BNC so you can rotate other DACs into your system. Lumin's app sounds good and has a reasonable UX. Aurender's A15 is also a good choice for an all-in-one and has similarly high-quality build/sound/features/app. Don't skimp on the switch (preferably one that has an OXCO clock and fiber optic i/o) and cables, as others have said, every component counts in the chain.

I don’t stream, but I do have very efficient speakers, and prefer tubes.

Having efficient speakers, I would encourage you to go tubes all the way, either separates, or integrated. I would go for more than needed, say 40-45 wpc, to have reserves for instantaneous needs.

Remote volume a requirement for me. Remote balance, rare, is a wonderful feature.

Think about how/where you might fit a TT and related phono stage in case you get tempted after you get your streaming up to speed.

OP - this is a hot topic, as others have suggested, if you search this topic you’ll find a lot of threads, guidance, discussion.  I am on the digital journey and here are some suggestions, humble learnings, and I’m still tweaking, taking some chances.

Know your system before you select a streamer / DAC.  If you’ve got a highly revealing system built around hearing every last micro detail, buckle up, everything in your digital chain will change, influence the sound in ways that will matter to you. If you have a more laid back system, one that plays well with poor recorded tracks, albums, this type of system will somewhat mask some of the warts that can surface in your digital chain.  
 

Synergy is absolutely key, many Streamer / DAC companies design their equipment to work best with their own products, you can pair a great streamer and DAC but if they aren’t designed to maximize each others potential, design you might not love the results.  Synergy also applies to the first point, take McIntosh gear, it has a signature sound that will play well with other equipment, mask some deficiencies in ways some other gear won’t, I make this point as it isn’t all about price, McIntosh gear is not low end, cheap gear.  It’s not to say McIntosh gear won’t shine with higher end Streamer / DAC’s it will, it is more forgiving than other higher end gear.
 

Interface - App development - a streamer is only as good as the app that supports it.  If the app stinks, you are unlikely to have a great experience with your streamer, even if you love the sound.  Read up on the app, the support, how often it’s updated, it’s an often overlooked feature that is critical.  
 

MQA - as others have stated - it’s not an indication on if a Streamer or DAC are quality products.  It’s more like a Home Theater Receiver saying it decodes Dolby Atmos.  There are $ 200 receivers that do and $8,000 that can.  
 

How you plan to use the digital set up is important as well - are you planning on streaming Qobuz / Tidal, playing CD’s or pulling FLAC or other files from your network.  You’d want to know that to allow you to choose a digital front end that does what you want it to do, focusing on having it do best what you plan to use it for the most.  
 

I’ve had the Node 2i, Lumin, Auralic, Krell, Parasound, MHDT, Anthem and probably some I’m forgetting, either DAC and or streamers.  Separates and  all in one solutions.  There differences and how apparent they were really depended on the rest of the gear.  In general, the differences in digital are subtle, they aren’t huge differences, swings.  That said, if you match the digital end with the rest of your gear those subtle differences are very noticeable, apparent.  Safest path is an all in one streamer / DAC from a company that has a great app, functionality with proven support, updates.  Aurender, Auralic, Lumin are standouts - products using Bluos which is the most mature platform.  
 

Good Luck! 

MQA is a scam, in light of modern high speed Internet and Quboz. It’s also lossy. The worst thing for me is that it locks you into their apodizing filter and I’ve found others perform better to my ears.

I think it's good to stay simple rather than try to blow out your budget.  How about a Rogue or ARC integrated to start you off?

Also, consider the room.  :)