data merge storage mt:settings {\
  despawn: [\
    { "id": "3", "display": { "text": "Standard", "type": "text" } },\
    { "id": "4", "display": { "text": "Fast", "type": "text" } },\
    { "id": "5", "display": { "text": "Hypersonic", "type": "text" } },\
    { "id": "1", "display": { "text": "Sloth", "type": "text" } },\
    { "id": "2", "display": { "text": "Slow", "type": "text" } }\
  ]\
}

data modify storage mt:settings despawn_speed set value 'standard'