175 is considered a long crank for someone of your size. 180 is extra long.
If you think of crank length as part of the total gearing from foot to tyre, then longer cranks give lower gears. By turning your foot through a larger circumference you will be able to turn a higher (cog-to-cog)gear with a lower cadence for the same power. You still use the same power, longer cranks dont magick power out of thin air.

Have you tried just running a lower gear with your current cranks. Many race bikes are quite highly geared, and if you just dont have the power to turn your gears, just get a larger cog or smaller chainwheel. Try the cheap solution before going for the expensive one.

Long cranks will cause you to flex your knee and hip joint through a greater range, which may be biomechanically inefficient . (Think of it as increasing your stride length in running).

Long cranks may cause you to ground your pedals on corners. Big size frames should be designed for long cranks, with a higher bottom bracket to prevent grounding.