JSFiddle - React, Tailwind, and code Playground

JavaScript

function elementsInOnlyOneArr(...arrays) {

  // de-dup and sort so we process the longest array first
  let sortedArrays = arrays.map(ar => [...new Set(ar)]).sort((a,b) => b.length - a.length);
  
  for (let ai1 = 0 ; ai1 < sortedArrays.length; ai1 ++) {
    for(let i = sortedArrays[ai1].length - 1; i >= 0; i --){
      let exists = false;
      let val = sortedArrays[ai1][i];   
      for(let ai2 = ai1 + 1 ; ai2 < sortedArrays.length ; ai2 ++) {
        let foundIndex = sortedArrays[ai2].indexOf(val);
        if (foundIndex >= 0) {
          exists = true;
          sortedArrays[ai2].splice(foundIndex,1);
          // do not break, check for match in the other arrays
        }
      }
      // if there was a match in any of the other arrays, remove it from the first one too!
      if (exists)
        sortedArrays[ai1].splice(i,1);
    }
  }
  // concat the remaining elements, they are all unique
  let output = sortedArrays[0];
  for(let i = 1; i < sortedArrays.length; i ++)
    output = output.concat(sortedArrays[i]);
    
  return output;
}

let arr1 = ['a', 'b', 'c', 'a', 'b']
let arr2 = ['a', 'd', 'b', 'c']
let arr3 = ['f', 'c', 'a']
console.log(elementsInOnlyOneArr(arr1,arr2,arr3));