$5000 budget for both DAC and headphone Amp. but kick out Chinese brand.....????to be honest I don't have any idea.....
according to the gear that you mentioned, don't think about Nuforce.....I pick CA dacmagic match with a chinese tube headphone Amp.
As a user of "Littledot", I recommand littledot DAC and the Littledot MKIV(standard ver.) tube headphone Amp.
P.S agree with 葵若葉 C-hing...trust your own audition ......