Uncaught TypeError: Cannot read properties of undefined (reading ‘target’) & (reading ‘value’)

After JQuery Version Upgrades to 3.5.0 from 2.14, I am receiving the following error, but I did not fully understand what the problem is,there is radio = event.target The error I received in the definition of Cannot Read Properties of Undefined (Reading ‘target’)
Anyone can you help me solve?*

var testMethod = {
    testSubMethod: function (event) {
    
        var radio = event.target;
        var isMultiInput = $('#MultipleInputYes').is(':checked');

        if (isMultiInput) {
            $('.divMultiInput').removeClass("dp-none");

            $('.divMinMaxVal').addClass("dp-none")
            $('#divMinMaxDate').addClass("dp-none")

            $('#divRgxWarnMsg').addClass("dp-none")

            $('#minValueInpt').val('');
            $('#maxValueInpt').val('');

            $('.divInputValUpper').addClass("dp-none");
            $('[name=ValueType]').val('');
            $('#inputValueTypeSelect').removeClass('required');
            $('#inputValueTypeSelect').removeClass('customError');

        }
        else if (!isMultiInput || radio.value == undefined) {
            $('.divMultiInput').addClass("dp-none");

            $('.divMinMaxVal').removeClass("dp-none");
            $('#divMinMaxDate').removeClass("dp-none");
            $('#divRgxWarnMsg').removeClass("dp-none")

            $('.divInputValUpper').removeClass("dp-none");
            $('[name=ValueType]').val('1');
            $('#inputValueTypeSelect').addClass('required');

            $('#divWarnMsg').css("display", "inherit");
            $('#placeHolderInpt').val('');
            $("#maskInpt").select2("val", "");

            if (radio.value == 'false') {
                $('#divInputValueType').prop('disabled', false);
                $('#divInputValueType').attr('style', '');
            }

            $('#htmlEditorDiv').css("display", "inherit");
            $('#useMultiLineDiv').css("display", "inherit");

            $("#Tags").tagit("removeAll");
        }
    },
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.0/jquery.min.js"></script>
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/select2.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/select2.min.js"></script>
<div class="radio radio-success">
<input type="radio" id="MultipleInputYes" value="true" name="IsMultiInput" onchange="testMethod.testSubMethod(this)">
<label for="MultipleInputYes"> Yes</label>
</div>

<div class="radio radio-success">
<input type="radio" id="MultipleInputNo" value="false" checked="checked" name="IsMultiInput" onchange="testMethod.testSubMethod(this)">
<label for="MultipleInputNo">No</label>
</div>