Hello,

Add this code to the Theme settings > Custom CSS > Global

body .product-grid-item .price,
body .single-product-page .summary-inner > .price {
        font-size: 0;
}
.single-product-page .summary-inner > .price > span:first-child {
   font-size: 22px;
}
.single-product-page .summary-inner > .price > small {
    font-size: 18px;
    margin-left: 6px;
}
body .product-grid-item .price > ins,
body .product-grid-item .price > span:first-child {
   font-size: 14px;
}
body .product-grid-item .price > del {
    font-size: 12px;
    margin-right: 3px;
}
body .product-grid-item > .price > small {
    font-size: 12px;
    margin-left: 4px;
}
body .single-product-page .summary-inner > .price > ins,
body .single-product-page .summary-inner > .price > span:first-child {
   font-size: 22px;
}
body .single-product-page .summary-inner > .price del {
    font-size: 22px;
    margin-right: 6px;
}

As for the menu, please provide page URL and your site admin access I will check how it is displayed and tell you how to remove

Best Regards