Hi, I am looking to upgrade from using Nokia 7 plus using SMSL M6 DAC with SMSL T2 valve amp with Millard E180f valve upgrade. Question is do I go for SMSL M500 MQA DAC and get full MQA unfolding or would I be better sticking to using the UAPP app which unfolds first MQA fold and produces 24bit/96khz quality and instead of the M500 , go for a better hifi DAC like the chord mojo? That’s the budget limit. Second upgrade , headphones, I have Sennheiser Momentum 2 on ears, using cable, HD25’s and HD280 Pro, (I like sennheiser ). The options I have in mind are HD650 or AKG K712? Or suggestions in same price band please.