He can't add pace, he either has it or he doesn't and it's clear at senior level he doesn't. However he is very intelligent and moves well.
Harry Kane was accused of being slow when young
He became quicker through a variety of changes - for example a running coach changed his running style (there are even professional 'gait analysts') , he increased his body strength, and even changed his breathing to get more oxygen into his body at the right times - all of which helped made him faster, better acceleration etc.
Harry has never been very fast but he became a lot faster than when 18, and I suspect Mikey will be advised on ways to increase his speed.
And the other way, which Mikey already has to some extent, is speed of thought and knowing where everyone else on the pitch is etc - Sherringham was never fast but his speed of thought allowed him to start running before other players had worked out what to do.