As @Photics suggested. window.location.href may work better.
But instead of trying to evaluate js in the onclick which can get confusing. have the onclick call a function , especially as you already have script tags in there, you may as well use them.
This will allow you to use the js syntax better with out worrying about evaluating strings to javascript.
Also , as he pointed out you are missing the second parameter "_self"
<form name="jump3">
<select name="menu" id="yearmenu" style="font-size : 16px; color: white; background: #4b6bb3;">
<option value="#">YEAR</option>
<option value="https://firesprinklerassoc.org/fire-sprinkler-saves-interactive-map-2020/">2020</option>
<option value="https://firesprinklerassoc.org/fire-sprinkler-saves-interactive-map-2021/">2021</option>
<option value="https://firesprinklerassoc.org/fire-sprinkler-saves-interactive-map-2022/">2022</option>
<option value="https://firesprinklerassoc.org/fire-sprinkler-saves-interactive-map-2023/">2023</option>
<option value="https://firesprinklerassoc.org/fire-sprinkler-saves-interactive-map-2024/">2024</option>
</select>
<input type="button" value="GO" style="display:none" id="gobutton3" onclick="myFunction()">
</form>
<script>
function myFunction(){
window.open(document.jump3.menu.options[document.jump3.menu.selectedIndex].value, '_self');
//jump2.reset();
}
document.querySelector("#yearmenu").addEventListener('change', function() {
document.querySelector("#gobutton3").dispatchEvent(new Event("click"));
});
</script>