To disable sidebar on the My Account or any other page edit the page and Choose without in 8theme Layout Options > Sidebar position http://prntscr.com/g2l687
To remove items from the My account menu go to WooCommerce > Settings > Account and remove endpoints for the items you don’t want to show http://prntscr.com/g2l6mk
Or you can create your own menu in Appearance > Menus > create the menu and choose it like My account in location settings.
Please provide wp-admin access in Private Content.
