/give @p minecraft:diamond_leggings{display:{Name:"{\"text\":\"Ohnezahns Hose\",\"color\":\"light_grey\"}"},
Enchantments:[{id:"minecraft:protection",lvl:10},{id:"minecraft:unbreaking",lvl:6969}],
AttributeModifiers:[
{AttributeName:"generic.maxHealth",Name:"generic.maxHealth",Amount:4,Operation:0,UUIDLeast:522120,UUIDMost:640784,Slot:"legs"},{AttributeName:"generic.armor",Name:"generic.armor",Amount:6,Operation:0,UUIDLeast:542041,UUIDMost:415191,Slot:"legs"},{AttributeName:"generic.armorToughness",Name:"generic.armorToughness",Amount:2,Operation:0,UUIDLeast:721496,UUIDMost:663359,Slot:"legs"},{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.2,Operation:2,UUIDLeast:552175,UUIDMost:607502,Slot:"legs"},
{AttributeName:"generic.movementSpeed",Name:"generic.movementSpeed",Amount:0.5,Operation:2,UUIDLeast:552175,UUIDMost:607502,Slot:"offhand"}],Unbreaking:1} 1


Execute:
/effect give @a[nbt={Inventory:[{Slot:-106b,id:"minecraft:heart_of_the_sea"}]}] speed 3 2