AleBa,
const obj = {
'6': '112',
'20': '51',
'22': '78',
'26': '34',
'32': '22',
'35': '358',
}
const objMax = obj => Object.fromEntries([Object.entries(obj).reduce(([_, max], [key, value]) => +max < +value ? [key, value] : [_, max])]);
console.log(objMax(obj))