According to the Help Guide, you should be okay as long as the batteries are not overheating beyond the limit shown. It only lists a minimum output current of 1.5 A and no specific mention of V or W specs, so I think you'd be okay.
You can try using the Xiaomi one and monitor the charging of the headphones to see if it causes an issue, if not then you know you can use that and then do the same with the Apple charger if you feel like you need a faster charge.
Hope this helps!
- JD
