loop to check combination of dropdown & checkbox in pure javascript

Good morning!
I have a page with 1 dropdown menu that has 24 options to select.
As well There are 12 checkboxes to select.
Each dropdown option and each checkbox has a predefined variable.
i.e.:
dropdown value="utcValue0 -> var utc0 and
checkbox value id="gameCheck" -> var gameTag
desired output here is a new variable var a = utc0 + gameTag;

My current solution works, however it is very tedious and terrible to read and there must be a whole lot easier way to handle this. I’m at the moment just defining each scenario 1 by 1.
Considering it’s 24 dropdown menus and 12 checkboxes this can not be the way..
I think it can be done with a smart nested loop, but I can’t come up with how to actually write that.

I’d highly appreciate some help! Thank you so much!

    <select name="hourSelector" id="hourSelectorID">
      <option value="utcValue0">0 - 1 UTC</option>
      <option value="utcValue1">1 - 2 UTC</option>
      <option value="utcValue2">2 - 3 UTC</option>
      <option value="utcValue3">3 - 4 UTC</option>                
      <option value="utcValue4">4 - 5 UTC</option>
      <option value="utcValue5">5 - 6 UTC</option>
    </select>

       <input type="checkbox" class="custom-control-input" id="gameCheck">
       <input type="checkbox" class="custom-control-input" id="purchCheck">
       <input type="checkbox" class="custom-control-input" id="inputCheck">

    var utc0 = 'created>"' + todayUTC + 'T00:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T01:00:00Z"';
    var utc1 = 'created>"' + todayUTC + 'T01:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T02:00:00Z"';
    var utc2 = 'created>"' + todayUTC + 'T02:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T03:00:00Z"';
    var utc3 = 'created>"' + todayUTC + 'T03:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T04:00:00Z"';
    var utc4 = 'created>"' + todayUTC + 'T04:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T05:00:00Z"';
    var utc5 = 'created>"' + todayUTC + 'T05:00:00Z"' + ' ' + 'created<"' + todayUTC + 'T06:00:00Z"';

var gameTag = 'whatever';
var purchTag = 'otherwhatever';
var eventTag = 'morewhatver';

  // grab input Hour
  var hourDropdown = document.getElementById("hourSelectorID");
  var selectedHour = hourDropdown.options[hourDropdown.selectedIndex].value;

    if (document.getElementById('gameCheck').checked) {
      if (selectedHour == 'utcValue0' ) {
        var a = utc0 + standardStuff + eventTag
      }
      if (selectedHour == 'utcValue1') {
        var a = utc1 + standardStuff + eventTag
      }
      if (selectedHour == 'utcValue2') {
        var a = utc2 + standardStuff + eventTag
      }
      if (selectedHour == 'utcValue3') {
        var a = utc3 + standardStuff + eventTag
      }
      if (selectedHour == 'utcValue4') {
        var a = utc4 + standardStuff + eventTag
      }
      if (selectedHour == 'utcValue5') {
        var a = utc5 + standardStuff + eventTag
      }
    }