Higher speed = slower clocks, but higher gravity (which is equivalent to higher acceleration) also = slower clocks.
The technical specs for GPS satellites give instructions on how to account for the satellites’ clocks both slowing down (because of their speed) and speeding up (because they are under lower gravity): in that case, the effect due to gravity is greater (i.e. overall the clocks run faster), so the clocks have to be artificially slowed to stay sync’d to clocks on Earth.
