I've been trying to solve the problem for a few days, and after several approaches I'm not getting anywhere. By testing several numbers, it shown the obviously correct number, but I got a few errors in the status...
Status

export const formatNumber = (n) => {
  let number = n;
  let suffix = [97, 92];
  let ret = "";

  //divide number as long as it has 3 digits; counts up the suffix
  //count up the second param, until we reach 122 (=z), we reset to 97(=a) and count up the first param
  while (number >= 1000) {
    number /= 1000;
    if (suffix[1] < 122) {
      suffix[1]++;
    } else {
      suffix[0]++;
      suffix[1] = 97
    }
  }
  const stringNumber = String(number);
  const i = stringNumber.indexOf(".");
  //console.log(test)
  //check for the point and build the number string; add trailing zeroes if none available
  if (i >= 0) {
    ret = stringNumber.substring(0,i) + "." + stringNumber.substring(i+1, i+3);
  } else {
    ret = stringNumber + ".00";
  }  

  switch (suffix[1]) {
    case 92:    //number is <1_000
      if (i >= 0) {
        return stringNumber.substring(0, i) + "." + stringNumber.substring(i+1, i+2);
      } else {
        return stringNumber + ".0";
      }
    case 93:    //number is < 1_000_000
      return ret + "K";
    case 94:    //number is < 1_000_000_000
      return ret + "M";
    case 95:    //number is < 1_000_000_000_000 (billion)
      return ret + "B";
    case 96:    //number is < 1_000_000_000_000_000 (trillion)
      return ret + "T";
    default:    //number is taller than a trillion and we use the suffix (97 = a; 122 = z)
      return ret + String.fromCharCode(suffix[0]) + String.fromCharCode(suffix[1]);
  }
}