const lookup = new Map();
for (const record of arrayWithDuplicates) {
  const key = record[2];
  
  if (!lookup.has(key)) {
    lookup.set(key, record);
    continue;
  }
  
  const other = lookup.get(key);
  if (record[1] > other[1]) {
    // Iteration order is based on insertion order. By removing the
    // current value first, the new value will be placed at the end.
    // If you don't care about the order, deletion can be omitted.
    lookup.delete(key);
    lookup.set(key, record);
  }
}

const result = Array.from(lookup.values());

let arr = arrayWithDuplicates
let unique = []
for (let i = 0; i < arr.length; i++) {
  let found = false;
  for (let j = 0; j < unique.length; j++) {
    if (arr[i][2] === unique[j][2]) {
      found = true;
      if (arr[i][1] > unique[j][1]) {
        unique[j] = arr[i]; 
      }
             break;
    }
  }
  if (!found) {
    unique.push(arr[i])
  }
}

let deduped = [...arrayWithDuplicates]; // take a copy

deduped.sort((a, b) => { // sorts in place
  if (a[0] < b[0]) return 1; // sort on names
  if (a[0] > b[0]) return -1;
  return b[1] - a[1]; // sort on second element
})

// reduce into an object keyed on state
deduped = Object.values(  // take only the values from the object
  deduped.reduce((acc, cur) => {
    const state = cur[2];
    if (!acc[state]) acc[state] = cur;
    return acc;
},{}))