Hello,

You have a header banner HTML block and you have enabled sticky column in it. I have disabled and it has solved issues:
Footer Missing on the desktop version (now missing? It was under Instagram feed)
Sidebar (filter prices etc) on shop pages on mobile not showing when clicked
Burger menu on mobile version not showing when clicked

As for the shop page. It is a functional page, please remove the content from it.

If you want to add content into the shop page in the top, follow these steps:

1. Enable Top filters in the Theme Settings > Shop > Shop filters https://gyazo.com/3564df2a5d658a0010b6c0ebd0b537d4

2. Enable Shop filters area always opened

3. Shop filters content type should be set Custom content

4. You can choose the HTML block with the content from the Shop filters custom content drop-down.

Best Regards