I copied JS code from one of those topics:

// Offcanvas hack for one page website
var nav_collapse = $('.offcanvas-menu .menu');
nav_collapse.click('li a', function(event) {
       event.preventDefault();
    $('.offcanvas-init').removeClass('offcanvas-active');
});

AND 2nd solution

For us, the single line at the end of main.js now works:

jQuery('.offcanvas-menu .menu').click(function(){jQuery('.close-offcanvas').trigger('click')});

Personally I cannot give you guarantee: if and how it works.