M-83
1000+ Head-Fier
I do a similar thing with my X5. It's the centre of my listening experience either as a transport, DAC to line out, or stand alone DAP. I love the flexibility of having multiple output options.
I would go x5 in a heartbeat but I'm unsure if the x5 alone (without a portable amp) would drive my alpha prime headphones well enough.
I may have to compromise and get an x3 with cayin c5 instead. Or wait for cayin n6 if it's close to being available in uk/eu.