Domenico, the difference is that currently you have a soundcard, geared mainly at gamers, that uses software to manipulate the sound to use all it's featues. As much as Creative parrot about their cards audio prowess, you have to disable all the software, all the scout and other software features, everything to get the best out of a decent set of cans to where the card is not manipulating the audio in anyway.
For £1000 in the Headphone DAC & Amp world, you have stacks of options for high performance audio. If you intend to use DSD, MQA, and want balanced and unbalanced outputs, I would be going with the recommendations Tinman has said above. Out of the two i'd probably go with the Topping EX5, and that then provides you options if you want add to that system later (the DAC on the EX5 is much stronger than the AMP side). However I don't see anything wrong with the Ifi Zen Dac V2 at this point. My only reservation with the Zen Dac V2 is I haven't seen/read any review yet where anyone has put it through an Analyzer.
You can read an Analyzer review of EX5 here:
https://www.audiosciencereview.com/...ex5-review-dac-and-headphone-amplifier.24341/