I'll take just the aux then, at least as long as I can. Aux (as in: 3.5mm jack on both ends or else on one end and the other one cinch or DIN to support even older devices) is something which has been working fairly universally to get music from any portable and even some not-so-portable players to amps in the past 30 years or so, extend to like 60 years to include anything compatible but with DIN (just a rough guess here, I still have some old Telefunken radio with an aux input via DIN and I'd estimate that is it's age; still works, moreover they really figured out nice warm bass from small speakers back then already). It's simple, it's a de facto standard, it really just works, it's a good idea (doubling as headphone out) and well-executed.

Bluetooth audio on the other hand tries to be all of that, but I never quite got the feeling it's there yet, after all those years, and I wonder it will ever be the same level of 'just works'.