Where do I go from here?

I have an old pair of ML CLS in my 2nd system.  Great speakers, you may want to use a sub with them especially with a tube amp.  

Yes, streaming is that simple.   You omitted the DAC.  You can get combo streamer/dac systems but they tend to be low end.

Hard wire your streamer to your router (wifi is a fool's errand)

Your DAC is the heart of the digital system.  Some DACs have volume control and since you don't plan to have other inputs, the DAC can replace your preamp.  I use Chord DAVE in this manner.

I use Qobuz, as do a lot of other members here.  Tidal appeals more to the hip hop crowd.

Finally, many of us use Roon to manage our listening pleasure.  Consider that.  If you think you might use Roon, avoid Aurender as they do't work with roon.

Jerry

if you want simple, get something like the Cambridge CXN V2 - streamer, DAC, Digital preamp - get Tidal so you can use Tidal Connect - Qobuz connect still in the long promise stage, forget Roon for now... WiFi is easy or if close to router than ethernet easy too...then when you system is fully going and you are familiar with streaming, then consider upgrade - the CXN V2 holds its value well

The choice to go straight to streaming is the right one today. 
 

Streaming can sound better than CDs and equivalent or better than vinyl… but it depends on the price range. Vinyl wins in the <$20K digital leg area (meaning, you have to pay a premium… say 20% more for digital to equal vinyl… ((streamer + DAC vs TT + Phonostage). Over that, you can get equal sound quality for about the same money between digital and analog. 
 

My rule of thumb is the investment in carefully chosen components should be around Streamer = DAC = Preamp = amp… But about 30% more on speakers.

I am hoping this helps point you in the right direction. Given the age of your equipment, you might value it at 1/2 original cost.

Price isn’t everything, but it is a good way to think about how to invest in components to shoot for a very complementary set of components where no component unnecessarily holds back the system.

I had a pair of Acoustat 2 + 2’s in the late 70’s that simply put me permanently in the audiophile camp and began my lifetime pursuit.

I think you really need to spend a few months streaming before you make any serious decisions about streaming or what to purchase...