Its okay, i think i managed to do it, I just removed the sidebar code and kept description code as :
.term-description, .page-description {

margin-left: -10px;
}

So the sidebar is back to its position on product pages, category pages and shop page :
https://www.sunnshinehk.com/shop/
https://www.sunnshinehk.com/product-category/lock-body-cylinder/
https://www.sunnshinehk.com/product/280ml-transparent-silicone-sealant/

i just have to add the description in all the category pages as a html block.

my only concern was I will not be able to show the number of products display on the shop page.