I'm simply wondering if the DX3 Pro+ is a sufficient enough DAC alone for the Asgard 3.
If my DX3 Pro+ is sufficient enough let alone to not buy anything else, I'm all ears.
If there are any other suggestions, I'm fully open to as well.
Whatever performs or is suggested for my Edition XS, I don't have a price limit.
the dx3 pro+ is a great amp/dac, it has great on-paper measurements and it has a lot of power in the amp department.
for your question "does it has enough power?" the answer is yes it does. will it benefit from more power? yes, it will most definitely will but that's not the main thing:
the main thing is the ability of the edition xs to scale really well, what is better scaling headphones? scaling is the way the headphones improve or deteriorate based on the chain it is connected to, better scaling = will sound better on a better chain, "bad" scaling = will sound about the same out of any chain strong enough to withstand them.
so what you need is not more power, but a higher-end amp compared to the dx3pro+. asgard 3 is a great choice, it is class AB (planars are happy when they are connected to A class or AB class amps) but I would recommend those ones since you said the budget isn't an issue: singxer sa-1 (600$), cayin iha-6 (700$-800$) and the king of amplifiers in my opinion and the best amp for planars from my listening experience: the ifi pro ican signature (2249$)