I agree with
@G T Audio that in general separates are superior to integrated units for the reasons he mentions, power supplies, shielding, etc.
And this is true for Audio Note. Audio Note integrated amplifiers are usually two separates in on box sharing one power supply. Take the Meishu Phono 300B integrated amplifier. You can buy this integrated amp as separates - an M2 Phono (or M2 Line and separate M2 Phono RIAA) and P3 300B stereo Power amp. If you separate all this out it sounds better than the Meishu Phono integrated. One thing great about Audio Note is that if you ever want to compare integrated to separates you can actually audition the EXACT same design and parts etc and compare them back and forth. The P3 is the identical power amp section that is in the Meishu - same parts etc. But of course, going separates is a lot more money.
Note: There can be an advantage to integrated products too: Short signal paths require less wiring and the best wiring is no wiring - so short wiring is better than long wiring. And a good designer making a good integrated will sound better than a so-so designer making separates. Having come back from listening to the one box Audio Note Meishu Phono Tonmesiter (basic entry level version) it was astonishing. If I were not a reviewer - this would be my amp. It's the best 300B I have ever heard. Big, heavy box - not exactly pretty but I understand why it's Audio Note's best selling amplifier. The Tonemiester is a lot better than the first version which wasn't my cup of tea.
I have owned the OTO Phono SE for the last 18 years but taking the M1 phono (which is the preamp in the OTO) allows for more amplifier choices and running that preamp with my Empress Silver monoblocks is vastly superior to the OTO.
You, like me, own the DAC0.1x and it's better than the DAC that is in the Cobra - my understanding is that the Cobra version is not a tube dac - it uses the chip but it's not the same thing. I did like the DAC chip more than a $2000ish CD player from Roksan that was connected to it.
But again when we talk separates - the Cobra is somewhat acting like a separate DAC for the Roksan one box player. What I would want to do is connect the 0.1x DAC to the Cobra then we can compare apples to apples.
I quite enjoyed the Cobra and IMO it's far better than what I have heard from Prima Luna or my prior Line Magnetic or what I have heard from Cayin (Cayin makes the transformers for both Line Magnetic and Prima Luna and Triode Labs (Line Magnetic makes the rest of the amp for Triode Labs). Interestingly Triode Labs makes the more affordable and best-looking amps of the lot so they are worth looking into as a cost-saving proposition. Cayin makes some great-looking amps too but the best ones only seem to be affordable here in Hong Kong and in China. The profit margin goes up too high IMO when they get to the west. I think the Cobra is the ugliest of the bunch because of the big Cobra put on the top of it and only available in black.
Still, it sounds better than pretty much any EL34 I have tried over the years precisely because it doesn't make me think Push-Pull sound. In fact, it was with the Rogers LS-3/5a (new version) where it interested me because it was the first time I actually liked the sound of those speakers. I am not surprised that Rogers has released their new tube amps and those are made by Audio Note.
You may also want to look at the Rogers e20 and possibly the A40 (they made a limited collector's edition run so they may be sold out by now) but these are both Audio Note amps under the Rogers label. Andy Whittle is the LS-3/5a guru and works for Audio Note 1 day and heads Rogers the other 4. My point is that the Rogers amps cost less than the Cobra and might be worth a look.
Ultimately, I would keep what you have. The Cobra is a really nice amp but like my OTO or the iZero or the SORO, they are inflexible. You can't upgrade them. They are great beginner amps because like all Audio Note gear they are auto-bias so if you are just starting out with tubes they sound great, the tubes last a long long time and are cheap to buy when they do need to be replaced. But none of them have preouts or prein.
And when making an upgrade I usually tell people to make sure to get a big upgrade. I don't think the Cobra would be an upgrade to what you have. I suppose you never know until you try. I would audition that Meishu Tonmesiter that could replace the Croft separates and keep your DAC. If your speakers are okay with 8 watts per channel - man it's a superb amplifier. I am considering the P3 Tonmeister - the power amp version of it. Interestingly the P3 has volume control for one source (I assume a passive attenuator) so in theory, if you only need one source you could get this instead of the integrated to save money. A second-hand one (rare) comes up it might be around the same money as a new Cobra.