from what i have learned , m600 has no options to change unless u have special firmware . its behaviour depends on the fw so i had motor that behaved differently - you have to try different fw's to try their internal settings - not available for enduser sadly ...
hey . so far i tried 510 and Yes. works no problem with 14s . shows 70% of battery with 30% of real capacity left so it will drain it empty without limiting power i expect
well . haven't u see flyon frame with 1600wh battery and tsdz8 1000w motor fitted in ?
you can buy entire bike without battery and motor for about 1000eur
almost all frames can be adapted to bafang with simple adapter. sometimes they are very cheap . I have currently two shimano frames with m560 fitted . and I'm in the process of building huskvarna ebikes also with bafang and 1200wh batteries