Take the wheel out and find something hard that you can slide up between the pads that fills the space between them completely. Squeeze the levers. Then you'll know better whether your issue is spongy feeling from trapped air or maybe something like the brake lever position adjustment.
Not that it should really have an effect on spongy brakes but have you measured your brake pads or rotor to see if they are within the limits specified by the mfr?
If you are losing any hydraulic fluid what so ever, then you will be getting air in them no matter how many times you bleed them.