caliper brakes don work as nice as v brakes ... no secret here

some caliper brakes have this " aero " syndrom to move the pads forward as they use longer pads and need clearance from the forklegs ..... old style caliper brakes usually are more straight down ...

Now I feel your pain ..lol ( not really .. but I have benn there ... )

can you try to mount the brake behind the fork ? This changes the geometry of the brake arms ....and usually give you more power ... if you can find a couple of shims between the brakepad and the arm which can rest against the forklegs you also take a lot of the flex out of the system .... and get better more linear modulation ...

Remember Sommatsch with her Brompton .. I got her maybe the very last in this world Magura "D" sized caliper mount bracket for the hydraulic brakes..... never heard from her again after that ..I sure hope it wasnt the brakes which failed..lol but this might be a viable ( exotic) possibility to make the bike slow down ...

Thor