bosch cx chainring haibike miranda

I have a 2017 Haibike HardSeven 6.0 which is a Boost spaced bike (27.5x3.0 tires, 148x12 rear thru-axle). The stock 18T chainring is simply not small enough. I have a 15T Connex sprocket, but because of the boost spacing, Haibike has a special chainring that spaces the sprocket out 5-8mm for...