Is there anything other than a Benchmark DAC?

Since you are going through a tube preamp my suggestion is the Schitt Yggi+ MIB. For the longest time I thought Schitt was mid-fi gear. However, after buying the Jotehuim R headphone amp for my RAAL headphones I started to try out more of their gear. Some of it is top notch.

You can't talk about tube DACs without mentioning Lampizator, you could get an Amber 4 for $4K but frankly given the quality of the other components in your systems you really don't want the weak link to be your source, you should really be looking at spending minimum $7-10K. 

OP, you mention that you may go with Mcintosh. If it includes a built in dac give that a shot for a while. They are actually quite good, I'd image the DAC2 module would compare nicely to a lot of top rated dacs.  

There’s DAC 2.2 SE by Abbas Audio on eBay in UK right now. You can easily convert it to 110V. I’m using the model 3.1 and it is by far the best DAC I owned so far. I'm using Sound Lab speakers with Atma Sphere electronics and Missing Bond cables.

I have had a DAC3 HGC  five years now ( Dr Frieckert- Hana Umani- Sutherland Little Loco- Benchmark AHB2- Harbeth SLH5) and find it hard to think that losing any of the low noise floor is worth a switch.

i have listened to a few other high end systems in homes and at dealers and my ears just get distracted at times by the noise floor as I’m used to just zero.

That being said paired with an amp other than Benchmark and you possibly will lose a bit of that blackness.

My take is is to find the least colored reproduction I can. ( and yes there are always arguments that any combo is colored in its own way… let the cable searchers get chatting!) I personally find the DAC 3 everything I need and I like to settle into a system without the swapping fever of looking for that little change.

i had my previous system mostly unchanged for 20 years and with very minimal outside listening experiences. I find that when I go listen to a system other than mine that my ears are “ calibrated” or rather just used to a sound and that it’s easy to feel the difference in an almost magnified way. It takes time to adjust and the question I always ask is will I want to just sit and listen to this every night? Be excited to listen? The equipment should just get out of the way, be neutral. 
A few nights ago I listened to a recording I know very well but cycled though the various pressings I have mixed by different folks and having a system that just presented the music with no bias of its own was heaven to to me.

Not great input for you! Lol

But just beware the chase.