Have you looked at this driver?
I am building BLF driver design that can handle up to 6S with a 28V LDO I have to order over the 18V I have now
Output is tested 5A so far but with upgraded parts I build today more that should reach 8A without any problems well in specification
price 22$ 5A
24$ up to 8A
ATM 42 and 47.5mm size availiable, 30mm planned