$('input#processLabel').keypress(function() {
  const dInput = $(this).val().replace(",",".");
  $(this).val(dInput);
});

<div id="upload_div" class="mt-3">
      <input class="inbox form-control" type="text" name="processLabel[]" id="processLabel" value="" onkeypress="return event.charCode >= 40 && event.charCode <= 57">
  </div>

document.getElementById("processLabel[]").addEventListener("keydown", function(event) {
    if (event.key === ",") {
        event.preventDefault();
        const selectionStart = event.target.selectionStart;
        const selectionEnd = event.target.selectionEnd;
        const inputValue = event.target.value;
        const modifiedValue = inputValue.substring(0, selectionStart) + '.' + inputValue.substring(selectionEnd);
        event.target.value = modifiedValue;
        event.target.setSelectionRange(selectionStart + 1, selectionStart + 1);
    }
});