Help me spend $$$$

I have been pursuing the best headphone system I could get for many decades as technology changed. I have found they are very similar to your main system. They can be as engaging as your main system. In fact I am listening to my system right now. You can see it under my user ID. 

So, the electronics, and in particular the headphone amp is critical. Just giving them enough power is one thing... feeding them massive, musical, as strong midrange can be life changing. I highly recommend looking at Woo amps. They only do headphone amps and they are at the top of the list of the best available. Highly recommended. I used to have a huge system, much hidden under my desk. This is a good way to get around the space problem. Consider a Woo amp and use the Bluesound streamer DAC. Put every penny you can into an amp. Then later you can upgrade the DAC and maybe later the streamer. 

I like that approach, but I first want to see how much I use the headphones. I tried this once before and didn't use them much but I didn't have a dedicated office either. I'd put some speakers in here but its too small so trying headphones.

Does Woo only make tube amps? I love tube amps and my main system has a Line Magnetic LM845 Premium and LTA ZOTL Reference 40+ amps in rotation. However, I live in Scottsdale now and heat is an issue. We already have $$$$$$ ac bills in the summer months and my office is pretty small so I don't want a space heater of an amp. Otherwise I might be looking at a Woo or Cayin or Feliks or some sort of tube amp.

I would not get a Matrix DAC for headphones maybe too bright.

I am currently listening to the RME DAC that I got for free (available used for $500-700). I am very impressed by this DAC on the phones. Now I am comparing this to a $12k DAC I had on it yesterday, but this RME is really solid and will likely be my office DAC, for headphones and 2-channel.

I got a Schiit Byggy DAC coming in next week. I have been saying that for 3 weeks now. The RME has impressed me to the point that I am feeling more confident about selling the Byggy DAC at over $3k. If the free DAC is almost as good as the $3k DAC, I would rather pocket the $3k.

If I were you, I would get a used RAAL SR1a with the special Schiit RAAL amp as a starter set. When you realize how great that thing is you can explore better amps. I am using a Schitt Aegir v1 amp that is 20-watts Class A. I got this amp used for $400 and today the RME DAC. 

The SR1a will get you closer to 2-channel speakers more than almost every headphone. The MySphere may be similar. I just sold a $7k tube amp to go with the $400 Aegir v1. I also decided to go with the SR1a over the $12k RAAL 1995 Immanis because I am a 2-channel person and the SR1a (or SR1b) is almost 2-channel.

Woo does makes a non-tube option—the Topaz 11:
https://wooaudio.com/amplifiers/wa11

Get yourself a Chord Mojo DAC and you’ve got a dandy compact desktop setup (also somewhat portable) right in your budget range. 

With your budget and heat considerations a Schiit option would be worth looking into…Of you don’t end up liking a Schiit system you should be able to sell quickly for a small loss of $