Levitation makes you move more slowly

I was playing in my creative minecraft world with my friend, we built a sky island with command blocks and structure blocks and stuff on top, I use "/effect @s levitation 10 10 true" and after I'm so much slower about a little less slower and soul sand while my friend is normal, we do a race to make sure and he is way faster... even with speed commands it didn't affect it and we go in his world and I'm normal speed